“Obesity paradox” has not an impact on minimally invasive anatomical lung resection

IntroductionThe paradoxical benefit of obesity, the ‘obesity paradox’, has been analyzed in lung surgical populations with contradictory results. Our goal was assessing the relationship of body mass index (BMI) to acute outcomes after minimally invasive major pulmonary resections.MethodsRetrospective review of consecutive patients who underwent pulmonary anatomical resection through a minimally invasive approach for the period 2014–2019. Patients were grouped as underweight, normal, overweight and obese type I, II and III. Adjusted odds ratios regarding postoperative complications (overall, respiratory, cardiovascular and surgical morbidity) were produced with their exact 95% confidence intervals. All tests were considered statistically significant at p < 0.05.ResultsAmong 722 patients included in the study, 37.7% had a normal BMI and 61.8% were overweight or obese patients. When compared with that of normal BMI patients, adjusted pulmonary complications were significantly higher in obese type I patients (2.6% vs 10.6%, OR: 4.53 [95%CI: 1.86–12.11]) and obese type II–III (2.6% vs 10%, OR: 6.09 [95%CI: 1.38–26.89]). No significant differences were found regarding overall, cardiovascular or surgical complications among groups.ConclusionsObesity has not favourable effects on early outcomes in patients undergoing minimally invasive anatomical lung resections, since the risk of respiratory complications in patients with BMI ≥ 30 kg/m² and BMI ≥ 35 kg/m² is 4.5 and 6 times higher than that of patients with normal BMI.     

The effect of BMI on clinicopathologic and functional outcomes after open radical prostatectomy

ObjectivesTo analyze the effect of body mass index (BMI) on pathologic and functional outcomes after open radical retropubic prostatectomy.Patients and methodsWe retrospectively analyzed 2,471 patients who underwent RP. Clinicopathologic and patient characteristics were compared with respect to patients' BMI (normal weight: BMI<25 kg/m² [n = 795], overweight: BMI≥25 kg/m² and<30 kg/m² [n = 1305], and obese: BMI≥30 kg/m² [n = 371]). Multivariable logistic and linear regression models were used to quantify the effect of BMI on pathologic and functional outcomes.ResultsCompared with normal weight patients, overweight and obese patients demonstrated higher pathologic Gleason grade and higher pathologic T stage, without any difference in preoperative prostate-specific antigen levels. Overweight and obese men were less likely to have a negative surgical margin (odds ratio (OR) 0.74 [confidence interval (CI) 0.65–0.84, P<0.001] for overweight men and OR 0.66 [CI 0.49–0.89, P<0.01] for obese men) and had a lower rate of postoperative erectile function (OR 0.60 [CI 0.48–0.76, P<0.001] for overweight patients and OR 0.34 [CI 0.27–0.44, P<0.001] for obese patients). Moreover, duration of surgery and intraoperative blood loss increased significantly with an increase in BMI. When using BMI as a continuous variable, the same trends were demonstrated. However, a lower rate of continence was not evident for overweight or obese men.ConclusionsIn contrast to many other studies, in this cohort of patients with prostate cancer, BMI was an independent risk factor for most analyzed pathologic and functional outcomes after radical prostatectomy, including negative surgical margin, potency, duration of surgery, and intraoperative blood loss.     

Body Mass Index in Lung Transplant Candidates: A Contra-indication to Transplant or Not?

Background

According to International Society of Heart and Lung Transplantation criteria, high body mass index (BMI; ≥30 kg/m²) is a relative contraindication for lung transplantation (LT). On the other hand, low BMI may be associated with worse outcome. We investigated the influence of pre-LT BMI on survival after LT in a single-center study.

Methods

Patients were divided according to the World Health Organization criteria into 4 groups: BMI <18.5 kg/m² (underweight), BMI 18.5–24.9 kg/m² (normal weight), BMI 25–29.9 kg/m² (overweight), and BMI ≥30 kg/m² (obesity). An additional analysis was made per underlying disease.

Results

BMI was determined in a cohort of 546 LT recipients, of which 28% had BMI <18.5 kg/m². Underweight resulted in similar survival (P = .28) compared with the normal weight group. Significantly higher mortality was found in overweight (P = .016) and obese patients (P = .031) compared with the normal-weight group. Subanalysis of either underweight (P = .19) or obese COPD patients (P = .50) did not reveal worse survival. In patients with interstitial lung disease, obesity was associated with increased mortality (P = .031) compared with the normal-weight group. In cystic fibrosis patients, underweight was not associated with a higher mortality rate (P = .12) compared with the normal-weight group.

Conclusions

Low pre-LT BMI did not influence survival rate in our cohort, independently from underlying disease.     

Effects of obesity on sperm retrieval,early embryo quality and clinical outcomes in men with nonobstructive azoospermia undergoing testicular sperm aspiration‐intracytoplasmic sperm injection cycles

The objective of this study was to assess the effects of body mass index (BMI) on sperm retrieval, early embryo quality and clinical outcomes in patients with nonobstructive azoospermia (NOA) undergoing testicular sperm aspiration‐intracytoplasmic sperm injection (TESA‐ICSI). A total of 3,005 infertile couples were evaluated between January 2010 and June 2017, including 1585 normal‐weight (BMI < 25 kg/m²), 847 overweight (BMI 25–29.99 kg/m²) and 573 obese (BMI ≥ 30 kg/m²) patients. We found no significant relationship between BMI and sperm retrieval rate (22.4%, 24.3% and 25.1%, p = 0.327) or sperm motility. Among the 705 patients with NOA who underwent TESA‐ICSI cycles, obese individuals had lower T levels and higher E2 levels than normal‐weight and overweight individuals. However, there were no significant differences in other male hormones (follicle stimulating hormone [FSH], luteinizing hormone [LH], or prolactin [PRL]) among the groups. We also found that the sperm parameters, embryo quality and clinical outcomes of patients with NOA undergoing TESA‐ICSI were not influenced by high BMI levels. In conclusion, this study demonstrated a lack of obvious effects of obesity on sperm retrieval, early embryo quality and clinical outcomes in infertile men undergoing TESA‐ICSI cycles, although T and E2 levels were affected.     

Does obesity have an effect on outcomes in triple-negative breast cancer?

Background

Among patients with breast cancer, obesity has been associated with an increased likelihood of having triple-negative breast cancer (TNBC). This association has been thought to be due to the antiapoptotic effects of obesity-related proteins. However, the effect of obesity on the outcomes in patients with TNBC remains unclear. We hypothesized that obesity would be associated with decreased overall survival and disease-free survival in these patients.

Materials and methods

A retrospective review of a prospectively maintained database was conducted of patients treated for breast cancer at an academic medical center from March 1998 to September 2011. The body mass index (BMI) of patients with TNBC was calculated at diagnosis. The patients were categorized as normal (BMI < 25 kg/m²), overweight (BMI 25–30 kg/m²), or obese (BMI > 30 kg/m²). The endpoints of overall survival and disease-free survival were analyzed.

Results

A total of 183 patients with TNBC were included for analysis. Of the 183 patients, 24 (13.1%) were normal (BMI < 25 kg/m²), 42 (23.1%) were overweight (BMI 25–30 kg/m²), and 117 (63.7%) were obese (BMI > 30 kg/m²). The median follow-up period was 42.5 months. Of the 183 patients, 2 (9.1%) died in the normal group, 10 (23.1%) died in the overweight group, and 25 (21.4%) died in the obese group (P = 0.28). The patients who were overweight or obese had larger tumors (P = 0.02), a higher T stage (P = 0.001), and higher tumor grade (P = 0.01) than the normal BMI patients. By Kaplan-Meier analysis, normal patients had higher overall survival than the overweight or obese patients, but this difference was not statistically significant (P = 0.29). Disease-free survival was also not significantly different (P = 0.91).

Conclusions

Despite an increased frequency of larger tumors, higher T stage, and higher tumor grade, obesity was not associated with decreased overall or disease-free survival in patients with TNBC.     

Robotic-assisted vertical sleeve gastrectomy in adolescents: Do BMI limits apply?

BackgroundRobotic-assisted vertical sleeve gastrectomy (VSG) in adolescent patients has been shown to have comparable outcomes to laparoscopic VSG. Recent data suggests that metabolic and bariatric surgery (performed using robotic and laparoscopic techniques) in patients with BMI ≥ 50 kg/m² have a higher risk of adverse events compared to those with BMI < 50 kg/m². The aim of this study was to compare the outcomes of robotic-assisted VSG in adolescents with a BMI above and below 50 kg/m².MethodsA retrospective analysis of all adolescents undergoing robotic-assisted VSG between January 2014 and December 2020. Subjects were categorized based on preoperative BMI; Group 1 (BMI < 50 kg/m²) or Group 2 (BMI ≥ 50 kg/m²). Data collection included patient demographics, preoperative BMI, total operative time, access time (i.e., total time for port-placement), 30 day complications, and 30 day hospital readmissions. Analysis was performed using chi-square, Fisher's Exact, and student t-test.ResultsTotal of 115 subjects (Group 1 N = 64 and Group 2 N = 51) were included. No differences in age or ethnicity were detected; however, Group 2 had a higher percentage of male patients (27.5% vs. 4.7%, respectively, p = 0.001). Mean operative times (Group 1 = 122.2 min vs. Group 2 = 121.6 min) and access times (Group 1 = 19.1 min vs. Group 2 = 19.7 min) were similar between groups. Thirty day complication rates were similar between groups (p = 0.133); however, there was a higher rate of hospital readmission in Group 1.ConclusionWhile recent data demonstrate an increased likelihood of adverse events occurring among patients with BMI ≥ 50 kg/m² undergoing robotic surgery, we observed no differences in intraoperative or early postoperative outcomes based on BMI in this robotic-assisted pediatric cohort.     

Overweight and obesity in adults with cystic fibrosis: An Italian multicenter cohort study

BackgroundOver the last decades aggressive interventions have been successful to improve nutritional outcomes in people with cystic fibrosis (CF). As a result, with improvement of life expectancy and new CFTR modulators, overweight and obesity are progressively becoming a source of concern for adult population and in developed countries.MethodsThis was a multicenter, observational, cross-sectional study of 321 adults with CF at three large CF centers in Italy. Patients were divided into three groups according to BMI classes, overweight and obesity (OW) group including patients with BMI ≥25 kg/m², normal weight (NW) group with BMI 18.6–24.9 kg/m² and underweight (UW) group with BMI ≤18.5 kg/m².ResultsWe demonstrated that prevalence of OW in adults with CF in Italy is 22%. OW status is independently associated with male sex (OR 3.520, P = 0.001), pancreatic sufficiency (OR 2.873, P = 0.014) and older age at diagnosis (1.015, P = 0.042). BMI correlated with ppFEV1 (r = 0.337; P<0.0001) with median ppFEV1 significantly higher in patients with OW than comparisons. We also reported preliminary data on unfavorable cardiovascular risk factors in a subgroup of patients, where median blood levels [IQR] of cholesterol and systemic hypertension [%] were significantly higher in the OW group than in the NW and UW.ConclusionsPeople with CF and OW is a relevant patient group that might deserve better definition and proper clinical management.     

Outcomes of the overweight and obese major trauma patient in the rural setting

PurposeOverweight and obese patients are more prevalent in rural and remote areas and are of major public health concern in Australia. We aimed to evaluate the mortality and morbidity of overweight and obese trauma patients in the rural Australian context.MethodThis was a retrospective cohort study on 207 major trauma patients (injury severity score [ISS] > 12) treated at the Mackay Base Hospital between 2018 and 2021. Data was extracted from the Mackay Base Hospital trauma database and hospital records. Outcomes were compared between body mass index (BMI) groups.ResultsThere were 164 males (79%) and 43 females (21%). The average BMI was 27.09 (standard deviation 5.46). 7 patients (3%) were in the underweight category (BMI < 18.5 kg/m²), 70 (34%) were of normal weight (BMI 18.5–24.9 kg/m²), 79 (38%) were overweight (BMI 25–29.9 kg/m²), and 51 (25%) were obese (BMI > 30 kg/m²). The majority of trauma was blunt (n = 203, 98%). Compared to patients with normal BMI, obese patients were significantly more likely to require intubation, intensive care unit (ICU) admission, and have a longer ICU stay. There were no significant differences in requirement for surgery, duration of surgery, hospital length of stay, ventilator time, or mortality (P > 0.05). However, subgroup analysis of the obese patient group showed an increased rate of complications (sepsis, acute kidney injury, fluid overload and pneumonia), longer ventilation times, hospital and ICU length of stay with increasing BMI in these patients.ConclusionThe majority of trauma presentations in our regional community are in overweight or obese patients. Overweight and obese patients are more likely to require intubation and have a longer intensive care unit admission than normal weight counterparts. Amongst obese patients, those with BMI > 40 (obesity class 3) are at significantly increased risk of complications.     

Obesity and perioperative outcomes in older surgical patients undergoing elective spine and major arthroplasty surgery

Study objectiveTo determine whether obesity status is associated with perioperative complications, discharge outcomes and hospital length of stay in older surgical patients.DesignSecondary analysis of five independent study cohorts (N = 1262).SettingAn academic medical center between 2001 and 2017 in the United States.PatientsPatients aged 65 years or older who were scheduled to undergo elective spine, knee, or hip surgery with an expected hospital stay of at least 2 days.MeasurementsBody mass index (BMI) was stratified as nonobese (BMI ≤ 30 kg/m²), obesity class 1 (30 kg/m² ≤ BMI < 35 kg/m²) or obesity class 2–3 (BMI ≥ 35 kg/m²). Primary outcomes included predefined intraoperative and postoperative complications, hospital length of stay (LOS), and discharge location. Univariate and multivariate logistic regression was performed.Main resultsObesity status was not associated with intraoperative adverse events. However, obesity class 2–3 significantly increased the risk for postoperative complications (IRR 1.43, 95% CI 1.03–1.95, P = 0.03), hospital LOS (IRR 1.13, 95% CI 1.02–1.25, P = 0.02) and non-home discharge destination (OR 1.95, 95% CI 1.35–2.81, P < 0.001) after accounting for patient related factors and surgery type.ConclusionsObesity class 2–3 status has prognostic value in predicting an increased incidence of postoperative complications, increased hospital LOS, and non-home discharge location. These results have important clinical implications for preoperative informed consent and provide areas to target for care improvement for the older obese individual.     

Body Mass Index and Unenhanced CT as a Predictor of Hepatic Steatosis in Potential Liver Donors

BackgroundIn living-donor liver transplantation, donor hepatic steatosis is crucial for both the donor and the recipient. Body mass index (BMI) and the unenhanced computed tomography liver attenuation index (CT LAI) are noninvasive methods to predict hepatic steatosis in living-donor liver candidates.AimTo analyze the diagnostic accuracy of CT LAI in conjunction with different BMI values for macrovesicular steatosis in living-donor liver candidates.MethodsA total of 264 potential liver donors were included. The diagnostic accuracy of 2 CT LAI cut-offs and 3 BMI cut-off values for the assessment of hepatic steatosis ≥15% and ≤5% was determined.ResultsUsing CT LAI, the area under the receiver operating characteristic curve was 0.97 (95% CI = 0.89–0.99) for hepatic steatosis ≥15% in donors with BMI <25 kg/m². For detecting hepatic steatosis ≥15%, a CT LAI ≤0 had specificities of 100%, 76.2%, and 55.6% and positive predictive values of 100%, 95.5%, and 93.5% for patients with BMI values <25 kg/m², 25 to 29.9 kg/m², and ≥30 kg/m², respectively. According to logistic regression analyses, only CT LAI ≤0 was found to be independently associated with hepatic steatosis ≥15%.ConclusionsIn donors with BMI <30 kg/m² and a CT LAI value >6, liver biopsy might be avoided. Biopsy may be reserved solely for donors with CT LAI value >0 and BMI ≥30 kg/m² as the diagnostic accuracy of computed tomography for predicting hepatic steatosis decreases with increasing BMI.     

Outcomes in Obese Kidney Transplant Recipients

BackgroundKidney transplantation (KT) in obese patients is controversial. The present study aimed to evaluate patient and graft survival and post-transplantation complications between obese and nonobese recipients.MethodsPatients (n = 3,054) receiving a KT from 1998 to 2008 were divided according to body mass index (BMI) into 3 groups for analysis: group I: BMI <30 kg/m² (nonobese); group II: ≥30–34.9 kg/m² (class I obese); and group III: ≥35 kg/m² (class II and III obese).ResultsMean BMIs were: group I (n = 2,822): 22.6 ± 3.3 kg/m²; group II (n = 185): 31.9 ± 1.3 kg/m²; and group III (n = 47): 36.8 ± 1.7 kg/m². There were no differences among the 3 groups in patient demographic variables regarding race, sex, or organ source. One-year (I, 98%; II, 98%; III, 95%) and 5-year (I, 90%; II, 92%; III, 89%) patient survival rates were similar among groups. Graft survival rates at 1 year were 96% for groups I and II and 91.5% for group III. Five-year graft survivals were: I, 81%; II, 96%; and III, 79%. The most common cause of graft loss was death, and the main cause of death was infection in all groups. Obese patients were more likely to experience wound dehiscence (I, 1.9%; II, 7.6%; III, 19.1%; P < .001), develop new-onset diabetes after transplantation (NODAT; I, 16.2%; II, 27%; III, 36%; P < .001), and have a prolonged length of hospital stay (I, 11.3 ± 11.4 d; II, 14.5 ± 14.3 d; III, 15.9 ± 16.7 d; P < .001).ConclusionsObese recipients demonstrated outcomes similar to nonobese patients regarding patient and graft survival. However, they had higher rates of prolonged length of hospital stay, wound dehiscence, and NODAT.     

Prostate cancer detection: The impact of obesity on Asian men

ObjectiveTo evaluate the impact of body mass index (BMI) on prostate cancer detection in biopsy-naive men presenting to a single tertiary hospital in Singapore.Materials and methodsWe retrospectively examined 458 men who underwent initial prostate biopsies between January 2012 and April 2014. Indications for biopsy were serum prostate-specific antigen level≥4.0 ng/ml, or digital rectal examination findings suspicious for malignancy, or both. Only men with serum prostate-specific antigen level <20 ng/ml were included. BMI categories were based on the World Health Organization recommendations (normal:<25.0, overweight: 25.0–29.9, and obese: ≥30).ResultsOf the 458 men included in our cohort, 125 (27.3%) men were positive for prostate cancer on biopsy, with 69 (15.1%) being clinically significant (Gleason≥7). Men with BMI≥25 kg/m² (41.7%) were younger (67.2 vs. 68.8 y, P = 0.030), had larger prostates (45.5 vs. 40.1 g, P = 0.014), and were more likely to have a positive biopsy finding (34.6% vs. 22.1%, P = 0.003). On multivariate analysis, being overweight or obese was associated with increased risk of having prostate cancer on biopsy (odds ratio [OR] = 2.61, 95% CI: 1.58–4.30, P<0.001 and OR = 3.26, 95% CI: 1.37–7.73 P = 0.007, respectively). The same trend was observed for clinically significant cancers but not for clinically insignificant cancers (OR = 3.57, 95% CI: 1.87–6.82, P<0.001 and OR = 3.86, 95% CI: 1.33–11.21, P = 0.013 for being overweight and obese, respectively).ConclusionAsian men with BMI≥25 kg/m² are at greater risk of having a positive initial biopsy result. The BMI threshold (BMI≥25 kg/m²) for Asian men to be at increased risk of prostate cancer detection on initial biopsy is lower than that of Western populations (BMI≥30 kg/m²).     

Renal Transplantation in Obese Patients: Experience in an Argentine Center

Possible complications of renal transplants in obese patients have raised concerns among nephrologists. We describe the outcomes of 110 renal transplant patients according to body mass index (BMI). Recipient BMI was calculated by using height and weight at time of transplantation and categorized according to World Health Organization guidelines. The patients' BMI values were as follows: underweight, n = 8 (7.27%); normal weight, n = 55 (50%); overweight, n = 30 (27.27%); and obese, n = 17 (15.45%). Mean age was significantly different among groups: underweight, 27.62 ± 7.57 years; normal weight, 44.98 ± 15.55 years; overweight, 50.53 ± 13.90 years; and obese, 52.11 ± 10.41 years (P < .05). Donor age and mean time of dialysis treatment were comparable in all groups. Underweight patients had a significantly larger proportion of living donors than those with higher BMIs. Calculated glomerular filtration rate (using the Modification of Diet in Renal Disease equation) were significantly different among the groups at 30, 60, and 90 days' posttransplantation. At 180 days, however, it was comparable: underweight, 62.96 ± 40.77 mL/min/1.73 m²; normal weight, 53.55 ± 26.23 mL/min/1.73 m²; overweight, 47.52 ± 16.37 mL/min/1.73 m²; and obese, 46.19 ± 17.56 mL/min/1.73 m² (P = .34). Incidence of delayed graft function was as follows: underweight, 0%; normal weight, 30.4%; overweight, 53.3%; and obese, 64.1% (P < .05). The incidence of surgical complications, incidence of rejection within the first 6 months' posttransplantation, and graft and patient survival rates over 6 months did not differ among the groups. Because transplantation in obese patients may be associated with higher risks and costs, the evaluation of each center experience is imperative. Longer term assessments are warranted, but our short-term results show that outcomes in overweight or obese renal transplant patients are comparable to those in patients with lower BMI.     

Extreme body mass index is associated with poor survival outcomes after radical cystectomy: a retrospective cohort study in a Chinese population

BackgroundBody mass index (BMI) has been evidenced to be a significant prognostic factor in multiple cancers. This retrospective study aimed to investigate the association between BMI and survival outcomes after radical cystectomy (RC) in patients with bladder cancer (BCa).MethodsClinical and pathological parameters of patients who were diagnosed with BCa and received RC between 2010 and 2018 were collected. The associations between BMI at surgery and clinicopathological features were examined. The prognostic value of BCa for overall survival (OS) and cancer-specific survival (CSS) was examined using the Kaplan-Meier method and Cox regression models.ResultsAmong the 217 patients enrolled in this study, 13 (6.0%), 121 (55.8%), 60 (27.6%), and 23 (10.6%) had a BMI value of <18.5 kg/m² (underweight), 18.5–23.9 kg/m² (normal), 24–27.9 kg/m² (overweight), and ≥28 kg/m² (obese), respectively. Underweight and obese patients tended to have poorer survival after RC than normal and overweight patients (P<0.05). Multivariable Cox regression revealed that extreme BMI was an independent predictor of both OS (BMI <18.5 vs. 18.5–27.9 kg/m², OR =2.675, 95% CI: 1.131–6.327, P=0.025; BMI ≥28 vs. 18.5–27.9 kg/m², OR =3.693, 95% CI: 1.589–8.583, P=0.002) and CSS (BMI <18.5 vs. 18.5–27.9 kg/m², OR =3.012, 95% CI: 1.180–7.687, P=0.021; BMI ≥28 vs. 18.5–27.9 kg/m², OR =3.801, 95% CI: 1.526–9.469, P=0.004), along with tumor stage and urinary diversion type.ConclusionsBeing underweight or obese is associated with a poor prognosis in patients with BCa undergoing RC. For patients who are preparing to undergo RC for BCa, controlling the BMI index through diet or exercise before surgery may contribute to the surgical curative effect and an improved prognosis.     

The association of body mass index with same-day hospital admission,postoperative complications,and 30-day readmission following day-case eligible joint arthroscopy: A national registry analysis

Study objectiveWe examined the association of body mass index (BMI) with hospital admission, same-day complications, and 30-day hospital readmission following day-case eligible joint arthroscopy.DesignRetrospective cohort study.SettingMulti-institutional.PatientsAdult patients undergoing arthroscopy of the knee, hip or shoulder in the outpatient setting.InterventionNone.MeasurementsUsing the American College of Surgeons National Surgical Quality Improvement Program dataset from 2012 to 2016, we examined seven BMI ranges: normal BMI (≥20 kg/m² and <25 kg/m²), underweight (<20 kg/m²), overweight (≥25 kg/m² and <30 kg/m²), Class 1 and 2 obese (≥30 kg/m² and <40 kg/m², reference variable), and severe obesity, which we divided into the following BMI ranges: ≥40 kg/m² and <50 kg/m², ≥50 kg/m² and <60 kg/m², and ≥60 kg/m². The primary outcome was hospital admission. Secondary outcomes included same-day postoperative complications and 30-day hospital readmission. We performed multivariable logistic regression and reported odds ratios (OR) and their associated 95% confidence interval (CI) and considered a p-value of <0.05 as statistically significant.Main resultsThere were a total of 99,410 patients included in the final analysis, in which there was a 2.6% rate of hospital admission. When compared to class 3 obesity, only those with BMI ≥50 kg/m² (OR 1.55, 95% CI 1.18–2.01, p = 0.005) had increased odds of hospital admission. There were no differences in 30-day hospital readmission or same-day postoperative complications.ConclusionWe found that only patients with BMI ≥50 kg/m² had increased odds for same-day hospital admission even when patient's comorbid conditions are optimized, suggesting that a BMI ≥50 kg/m² may be used as a sole factor for patient selection in patients undergoing joint arthroscopy. For patients with BMI <50 kg/m², we recommend that BMI alone should not be solely used to exclude patients from having joint arthroscopies performed in an outpatient setting, especially since this patient group makes up a significant proportion of joint arthroscopy.     

Relationship Between Mortality and BMI After Fracture: A Population‐Based Study of Men and Women Aged ≥40 Years

Fractures in obese older individuals contribute significantly to the overall burden on primary health care, but data on their impact on mortality are lacking. We studied the association between obesity and mortality following hip and nonhip clinical fractures in a retrospective, population‐based cohort study. The Sistema d'Informació pel Desenvolupament de la Investigació en Atenció Primària (SIDIAP^Q) database contains primary care computerized medical records of a representative sample of >2.1 million people (35% of the population) in Catalonia (Spain), linked to hospital admissions data. We included in this analysis anyone aged 40 years and older suffering a hip or nonhip clinical fracture in 2007 to 2009 in the SIDIAP^Q database. The main exposure was the most recent body mass index (BMI) measured before fracture, categorized as underweight (<18.5 kg/m²), normal (18.5 to <25 kg/m²), overweight (25 to <30 kg/m²), and obese (≥30 kg/m²). Furthermore, the study outcome was all‐cause mortality in 2007 to 2009 as provided to SIDIAP^Q by the National Office of Statistics. Time to death after fracture was modeled using Cox regression. Multivariate models were adjusted for age, gender, smoking, alcohol intake, oral glucocorticoid use, and Charlson comorbidity index. Within the study period, 6988 and 29,372 subjects with a hip or nonhip clinical fracture were identified and followed for a median (interquartile range) of 1.17 (0.53–2.02) and 1.36 (0.65–2.15) years, respectively. Compared to subjects of normal weight, adjusted hazard ratios (HRs) for mortality in overweight and obese subjects were 0.74 (95% CI, 0.62–0.88; p = 0.001) and 0.74 (95% CI, 0.60–0.91; p = 0.004) after hip and 0.50 (95% CI, 0.32–0.77; p = 0.002), 0.56 (95% CI, 0.36–0.87; p = 0.010) after nonhip fracture. In conclusion, the highest mortality was observed in individuals with low BMI, but compared to subjects of normal weight, obese and overweight individuals survived longer following fracture. The latter observation is consistent with data reported in other chronic conditions, but the reasons for reduced mortality in obese and overweight subjects when compared to those of normal weight require further research. © 2014 American Society for Bone and Mineral Research.     

Underweight patients are the highest risk body mass index group for perioperative adverse events following stand-alone anterior lumbar interbody fusion

BACKGROUND CONTEXTPrior studies investigating the association between Body Mass Index (BMI) and patient outcomes following spine surgery have had inconsistent conclusions, likely owing to insufficient power, confounding variables, and varying definitions and cutoffs for BMI categories (eg, underweight, overweight, obese, etc.). Further, few studies have considered outcomes among low BMI cohorts.PURPOSEThe current study analyzes how anterior lumbar interbody fusion (ALIF) perioperative outcomes vary along the BMI spectrum, using World Health Organization (WHO) categories of BMI.STUDY DESIGN/SETTINGA retrospective cohort study.PATIENT SAMPLEPatients undergoing stand-alone one or two-level anterior lumbar interbody fusion (ALIF) found in the 2005–2018 American College of Surgeons National Surgical Quality Improvement Program (NSQIP) databases.OUTCOME MEASURESThirty-day adverse events, hospital readmissions, post-operative infections, and mortality.METHODSStand-alone one or two-level ALIF surgical cases were identified and extracted from the 2005–2018 National Surgical Quality Improvement Program (NSQIP) database. Posterior cases and those primary diagnoses of trauma, tumor, infection, or emergency presentation were excluded. Patients were then binned into WHO guidelines of BMI. The incidence of adverse outcomes within 30-day post-operation was defined. Odds ratios of adverse outcomes, normalized to the average risk of normal-weight subjects (BMI 18.5–24.9 kg/m³), were calculated. Multivariate analysis was then performed controlling for patient factors.RESULTSIn total, 13,710 ALIF patients were included in the study. Incidence of adverse events was elevated in both the underweight (BMI<18.5 kg/m³) and super morbidly obese (>50 kg/m³), however, multivariate risks for adverse events and postoperative infection were elevated for underweight patients beyond those found in any other BMI category. No effect was noted in these identical variables between normal, overweight, obese class 1, or even obese class 2 patients. Multivariate analysis also found overweight patients to show a slightly protective trend against mortality while the super morbidly obese had elevated odds.CONCLUSIONSUnderweight patients are at greater odds of experiencing postoperative adverse events than normal, overweight, obese class 1, or even obese class 2 patients. The present study identifies underweight patients as an at-risk population that should be given additional consideration by health systems and physicians, as is already done for those on the other side of the BMI spectrum.     

Body mass index and risk of perioperative cardiovascular adverse events and mortality in 34,744 Danish patients undergoing hip or knee replacement

Background and purpose — Obesity is a risk factor for osteoarthritis in the lower limb, yet the cardiovascular risks associated with obesity in hip or knee replacement surgery are unknown. We examined associations between body mass index (BMI) and the risk of a major adverse cardiovascular event (MACE: ischemic stroke, acute myocardial infarction, or cardiovascular death) or the risk of all-cause mortality in a nationwide Danish cohort of patients who underwent primary hip or knee replacement surgery.

Methods — Using Danish nationwide registries, we identified 34,744 patients aged ≥ 20 years who underwent elective primary hip or knee replacement surgery between 2005 and 2011. We used multivariable Cox regression models to calculate the 30-day risks of MACE and mortality associated with 5 BMI groups (underweight (BMI < 18.5 kg/m²), normal weight (18.5–24 kg/m²), overweight (25–29 kg/m²), obese 1 (30–34 kg/m²), and obese 2 (≥ 35 kg/m²)).

Results — In total, 232 patients (0.7%) had a MACE and 111 (0.3%) died. Compared with overweight, adjusted hazard ratios (HRs) were 1.2 (95% CI: 0.4–3.3), 1.3 (0.95–1.8), 1.6 (1.1–2.2), and 1.0 (0.6–1.9) for underweight, normal weight, obese 1, and obese 2 regarding MACE. Regarding mortality, the corresponding HRs were 7.0 (2.8–15), 2.0 (1.2–3.2), 1.5 (0.9–2.7), and 1.9 (0.9–4.2). Cubic splines suggested a significant U-shaped relationship between BMI and risks with nadir around 27–28.

Interpretation — In an unselected cohort of patients undergoing elective primary hip or knee replacement surgery, U-shaped risks of perioperative MACE and mortality were found in relation to BMI. Patients within the extreme ranges of BMI may warrant further attention.     

The Influence of Obesity on Hospital Admission After Outpatient Foot and Ankle Surgery

We examined the association of body mass index (BMI) with sociodemographic data, medical comorbidities and hospital admission following ambulatory foot and ankle surgery. We conducted an analysis utilizing data from the American College of Surgeons National Surgical Quality Improvement Program database from 2007 to 2016. Adult patients who underwent ankle surgery defined as ankle arthrodesis, ankle open reduction and internal fixation, and Achilles tendon repair in the outpatient setting. We examined 6 BMI ranges: <20 kg/m² underweight, ≥20 to <25 kg/m² normal weight, ≥25 to <30 kg/m² overweight, ≥30 to <40 kg/m² obese, ≥40 kg/m²to <50 kg/m² severely obese, and ≥50 kg/m² extremely obese. The primary outcome was hospital admission. We performed multivariable logistic regression and reported odds ratios (OR) and their associated 95% confidence interval (CI) and considered a p value of <.05 as statistically significant. Data extraction yielded 13,454 adult patients who underwent ambulatory ankle surgery. We then performed listwise deletion to exclude cases with missing observations. After excluding 5.4% of the data, the final study population included 12,729 patients. The overall rate of hospital admission was in the population was 18.6% (2,377/12,729). The overall rate of postoperative complications was 0.03% (4/12,729). We found no significant association of BMI with hospital admission following multivariable logistic regression. We recommend that BMI alone should not be solely used to exclude patients from having ankle surgery performed in an outpatient setting, especially since this patient group makes up a significant proportion of orthopedic surgery.     

Impact of pretransplant recipient body mass index on post heart transplant mortality: A systematic review and meta‐analysis

The ISHLT's 2016 Guidelines on the selection of heart transplant (HT) candidates recommends weight loss prior to listing for persons with body mass (BMI) index greater than 35 kg/m². We conducted a systematic review to assess the impact of BMI on all‐cause mortality. We searched to identify eligible observational studies that followed HT recipients. We used the GRADE system to quantify absolute effects and quality of evidence, and meta‐analyzed survival curves to assess post‐transplant mortality across BMI categories. We found a significantly increased risk of mortality in patients with BMI > 30 kg/m² across all age categories, independently of transplant era and study source (BMI 30‐34.9: HR 1.10, 95% CI 1.04‐1.17; BMI ≥ 35: HR 1.24, 95% CI 1.12‐1.38). We also found an increased risk of death in underweight (BMI < 18.5 kg/m²) candidates over 39 years of age (Age 40‐65: HR 1.24, 95% CI 1.02‐1.53; Age > 65: HR 1.70, 95% 1.13‐2.57). We found obesity and underweight BMI to be associated with mortality post‐HT. The similar and overlapping increased risk of mortality in patients with BMI 30‐34.9 and BMI ≥ 35 does not support the recently updated ISHLT guidelines. Future evidence in the form of randomized controlled trials is required to assess effectiveness of interventions targeting obesity‐related comorbidities and weight management.