Accuracy of Medicare claims-based diagnosis of acute myocardial infarction: estimating positive predictive value on the basis of review of hospital records

Background

Many cardiovascular epidemiologic studies rely on diagnosis codes in health care claims databases. Despite important changes in the care and diagnosis of acute myocardial infarction (AMI), the validity of hospital discharge diagnosis codes for AMI in the US Medicare system has not been recently examined. Our objective was to examine the accuracy of International Classification of Diseases—ninth revision—Clinical Modifications (ICD-9-CM) discharge diagnosis codes and diagnosis-related groups (DRG) codes for AMI in a Medicare claims database.

Methods

We sampled hospitalization episodes from Medicare beneficiaries in Pennsylvania during 1999, 2000, or both. We used Medicare data to identify patients with hospitalizations containing indicators of AMI (ICD-9-CM diagnosis codes 410.X0 and 410.X1 or DRG codes 121, 122, and 123). Hospital records for these episodes were reviewed by trained abstractors using World Health Organization criteria for diagnosing AMI. We then calculated the positive predictive value of Medicare claims-based definitions of AMI.

Results

Of 2200 hospitalization episodes with Medicare diagnosis codes suggestive of AMI, 2022 hospital records (91.9%) were obtained. The positive predictive value for a primary Medicare claims-based definition was 94.1% (95% CI, 93.0%-95.2%). Positive predictive values for alternative claims-based definitions ranged slightly, with the definition including DRG codes and length-of-stay restrictions yielding the highest positive predictive value, 95.4% (95% CI, 94.3%-96.4%). Subjects with a history of myocardial infarction had a significantly lower positive predictive value than subjects without a history of myocardial infarction (88.1% vs 94.6%, P <.001).

Conclusions

In this study, we observed high positive predictive values for a Medicare claims-based diagnosis of AMI and a diagnosis based on structured hospital record review.     

Nonalcoholic fatty liver disease in Japanese patients with severe obesity who received laparoscopic Roux-en-Y gastric bypass surgery (LRYGB) in comparison to non-Japanese patients

Background. The number of patients with morbid obesity is increasing worldwide. However, the prevalence of morbid obesity is still low in Japan, and therefore few systematic investigations of liver dysfunction in this population have so far been carried out. This study aimed to investigate the clinical characteristics in severe obese Japanese patients undergoing laparoscopic Roux-en-Y gastric bypass surgery (LRYGB). Methods. Eighty-four patients with severe obesity, including 61 Japanese and 23 non-Japanese patients, were analyzed. Results. The mean body mass index (BMI) was 43.7 ± 7.8 kg/m², and there was no difference between Japanese and non-Japanese patients. Nonalcoholic fatty liver disease (NAFLD) was observed in 45/59 (76.2%) of the Japanese patients. Although there were no differences in the BMI and body weight, serum ALT was higher in Japanese patients in comparison to non-Japanese patients (P < 0.05). The indices for insulin resistance were significantly higher in the Japanese patients in comparison to non-Japanese patients (P < 0.01). The liver/spleen computed tomography (CT) ratios were lower in Japanese patients (P < 0.05). The laboratory data and BMI significantly improved at 1 year after LRYGB in both groups. Conclusions. Racial difference may exist difference may exist in NAFLD in patients with severe obesity. When the BMI is similar, liver dysfunction among Japanese patients with severe obesity tends to be higher than in non-Japanese patients. Japanese patients with severe obesity must therefore reduce their body weight to a greater degree in comparison to non-Japanese patients with the same BMI. LRYGB can achieve effective weight control and lower ALT levels in Japanese patients with severe obesity.     

Coronary stent implantation in patients with a single coronary artery--a report of 3 cases

An isolated single coronary artery is a rare congenital anomaly and a cause of cardiac ischemia, congestive heart failure, and sudden cardiac death. Reported here are 3 cases of single coronary artery with acute myocardial infarction in which coronary stenting was performed. Also reported are the coronary blood flow patterns of the right coronary artery arising from the single left coronary artery.     

Infective endocarditis caused by lactobacillus

Lactobacillus (LB) is a gram-positive rod-shaped bacterium that inhabits the oral cavity, gastrointestinal tract, vagina and nasal cavity. Although LB plays a role in the prevention of infections caused by pathogenic bacteria, it causes some critical infectious diseases such as infective endocarditis (IE). IE due to LB is rare; however, early diagnosis and early treatment are important because of its high mortality rate. We report the onset of IE after otologic treatment in a heavy drinker of alcohol, the second case of IE due to LB in Japan.     

Combination Analysis in Genetic Polymorphisms of Drug-Metabolizing Enzymes CYP1A2, CYP2C9, CYP2C19, CYP2D6 and CYP3A5 in the Japanese Population

The Cytochrome P450 is the major enzyme involved in drug metabolism. CYP enzymes are responsible for the metabolism of most clinically used drugs. Individual variability in CYP activity is one important factor that contributes to drug therapy failure. We have developed a new straightforward TaqMan PCR genotyping assay to investigate the prevalence of the most common allelic variants of polymorphic CYP enzymes CYP1A2, CYP2C9, CYP2C19, CYP2D6 and CYP3A5 in the Japanese population. Moreover, we focused on the combination of each genotype for clinical treatment. The genotype analysis identified a total of 139 out of 483 genotype combinations of five genes in the 1,003 Japanese subjects. According to our results, most of subjects seemed to require dose modification during clinical treatment. In the near future, modifications should be considered based on the individual patient genotype of each treatment.     

Prognostic Impact of Early Versus Late Initiation of Renal Replacement Therapy Based on Early Warning Algorithm in Critical Care Patients With Acute Kidney Injury

The aim of our study is to evaluate the impact of early vs. late initiation of continuous renal replacement therapy (CRRT), defined by clinical information system (CIS) software using an early warning algorithm based on acute kidney injury network (AKIN) stages, on survival outcome of critically ill intensive care unit (ICU) patients with acute kidney injury (AKI). Of 1144 patients (mean [SD] age: 61.3 [17.9] years, 57.7% were males) hospitalized in ICU over a 2‐year‐period from January 2016 to December 2017, a total of 272 patients who had developed AKI requiring CRRT were included in this retrospective cross‐sectional study. Data on patient demographics (age, gender), reason for ICU hospitalization, AKIN stage, Sequential Organ Failure Assessment (SOFA) score, Acute Physiology and Chronic Health Evaluation II (APACHE II) score, indications for CRRT, and time of CRRT initiation with respect to AKIN early warning algorithm were retrieved from hospital records and the CIS software database. Survivorship status was assessed based on total, in‐hospital and 90‐day post‐discharge mortality rates and analyzed with respect to CRRT onset before vs. after AKIN alarm. CRRT was initiated before the AKIN alarm in 41(15.0%) patients, and after the AKIN alarm in 231(85.0%) patients involving treatment within 0–24 h of alarm in 146 (63.2%) patients and within 24–120 h of alarm in 85 (36.8%) patients. Mortality occurred in 175 (64.3%) patients involving 25 (61.0%) out of 41 patients who received CRRT before AKIN alarm and 150 (64.9%) out of 231 patients who received CRRT after AKIN alarm. Mortality rate was significantly higher in those who received CRRT 24–120 h vs. 0–24 h after the AKIN alarm (82.4% vs. 54.8%, P < 0.001). Pre‐ and post‐CRRT SOFA scores were significantly lower in patients who received CRRT 0–24 h vs. 24–120 h after the AKIN alarm (P = 0.009 and P = 0.004, respectively), while pre‐CRRT APACHE II scores were significantly lower in patients who received CRRT before vs. after the AKIN alarm (P = 0.008). In conclusion, our findings indicate the potential role of using AKIN stage‐based early warning system in guiding time to start CRRT and improved survival in critically ill patients with AKI, provided that the CRRT was initiated within the early (first 24 h) of the alarming AKIN Stage II–III events. Future well‐designed clinical trials addressing early vs. late initiation of CRRT in critical care patients with AKI are needed to find and answer to the ongoing controversy and help clinicians in refining their indications for starting CRRT.