Understanding and using time series analyses in addiction research

Time series analyses are statistical methods used to assess trends in repeated measurements taken at regular intervals and their associations with other trends or events, taking account of the temporal structure of such data. Addiction research often involves assessing associations between trends in target variables (e.g. population cigarette smoking prevalence) and predictor variables (e.g. average price of a cigarette), known as a multiple time series design, or interventions or events (e.g. introduction of an indoor smoking ban), known as an interrupted time series design. There are many analytical tools available, each with its own strengths and limitations. This paper provides addiction researchers with an overview of many of the methods available (GLM, GLMM, GLS, GAMM, ARIMA, ARIMAX, VAR, SVAR, VECM) and guidance on when and how they should be used, sample size det ermination, reporting and interpretation. The aim is to provide increased clarity for researchers proposing to undertake these analyses concerning what is likely to be acceptable for publication in journals such as Addiction. Given the large number of choices that need to be made when setting up time series models, the guidance emphasizes the importance of pre‐registering hypotheses and analysis plans before the analyses are undertaken.     

Abstracts from other journals

The aim of the present study was to clinically evaluate fissure sealants on the occlusal fissures and buccal pits of permanent first and second molars after 20 and 15 years, respectively. The population consisted of 72 children, each of whom had had their four first molars sealed between 1977 and 1980. At the annual examinations, all caries-free, newly erupted second molars were sealed. When sealant was applied to the second molars, the first molars were checked and sealant was reapplied to those that had deficient sealants. At the follow-up, when the subjects were 26–27 years of age, 27 in the original group had moved from the community. Thus, the present result is based on 45 subjects. One hundred and fifty-three sealed first molars and 161 sealed second molars were available for inspection. At the follow-up examination of the first molars 20 years after sealant had been applied, 65% showed complete retention, 22% partial retention without caries, and 1306 caries or restoration in the occlusal fissures or buccal pits. At the 15-year follow-up of the second molars, the corresponding figures were 65%, 30% and 5%, respectively. Of the restored or carious molars, significantly more were found in the mandible than in the maxilla ( P  < 0.001). This longitudinal study showed that pit and fissure sealants, applied during childhood, have a long-lasting, caries-preventive effect.     

Getting back to equal: The influence of insurance status on racial disparities in the treatment of African American men with high-risk prostate cancer

ObjectivesTreating high-risk prostate cancer (CaP) with definitive therapy improves survival. We evaluated whether having health insurance reduces racial disparities in the use of definitive therapy for high-risk CaP.Materials and methodsThe Surveillance, Epidemiology, and End Results Program was used to identify 70,006 men with localized high-risk CaP (prostate-specific antigen level >20 ng/ml or Gleason score 8–10 or stage>cT3a) diagnosed from 2007 to 2010. We used multivariable logistic regression to analyze the 64,277 patients with complete data to determine the factors associated with receipt of definitive therapy.ResultsCompared with white men, African American (AA) men were significantly less likely to receive definitive treatment (adjusted odds ratio [AOR] = 0.60; 95% CI: 0.56–0.64; P<0.001) after adjusting for sociodemographics and known CaP prognostic factors. There was a significant interaction between race and insurance status (P_interaction = 0.01) such that insurance coverage was associated with a reduction in racial disparity between AA and white patients regarding receipt of definitive therapy. Specifically, the AOR for definitive treatment for AA vs. white was 0.38 (95% CI: 0.27–0.54, P<0.001) among uninsured men, whereas the AOR was 0.62 (95% CI: 0.57–0.66, P<0.001) among insured men.ConclusionsAA men with high-risk CaP were significantly less likely to receive potentially life-saving definitive treatment when compared with white men. Having health insurance was associated with a reduction in this racial treatment disparity, suggesting that expansion of health insurance coverage may help reduce racial disparities in the management of aggressive cancers.     

Comparison of patient reported outcomes after Triathlon? and Kinemax Plus prostheses

INTRODUCTION

The Triathlon^® (Stryker, Kalamazoo, MI, US) total knee replacement was designed to improve patient function and survivorship. The aim of this study was to determine whether the Triathlon^® prosthesis produces better patient reported outcomes than a previous design by the same manufacturer, the Kinemax Plus.

METHODS

The outcome of 233 knees of patients with a mean age of 68 years (range: 40–80 years) who received the Kinemax Plus prosthesis were compared with the outcomes of 220 knees of patients with a mean age of 70 years (range: 42–90 years) who received the Triathlon^® prosthesis. Data were collected via postal questionnaire prior to surgery as well as at 8–12 weeks and at 1 year following surgery. Validated questionnaires were used including the WOMAC^® (Western Ontario and McMaster Universities) pain and function scales, the Knee injury and Osteoarthritis Outcome Score quality of life scale and the self-administered patient satisfaction scale.

RESULTS

This study found that patients who had the Triathlon^® prosthesis had significantly better pain relief (p<0.0001), function (p=0.028), knee related quality of life (p<0.0001) and satisfaction (p=0.0003) at three months after surgery than those who received the Kinemax Plus prosthesis. In addition, knee related quality of life (p=0.002) and satisfaction (p=0.021) were significantly higher at one year after surgery in Triathlon^® patients.

CONCLUSIONS

The findings suggest that return to function and reduction in pain may occur more quickly in patients with a Triathlon^® prosthesis than in those with the Kinemax Plus.     

Alvimopan Accelerates Gastrointestinal Recovery After Radical Cystectomy: A Multicenter Randomized Placebo-Controlled Trial

Background

Radical cystectomy (RC) for bladder cancer is frequently associated with delayed gastrointestinal (GI) recovery that prolongs hospital length of stay (LOS).

Objective

To assess the efficacy of alvimopan to accelerate GI recovery after RC.

Design, setting, and participants

We conducted a randomized double-blind placebo-controlled trial in patients undergoing RC and receiving postoperative intravenous patient-controlled opioid analgesics.

Intervention

Oral alvimopan 12 mg (maximum: 15 inpatient doses) versus placebo.

Outcome measurements and statistical analysis

The two-component primary end point was time to upper (first tolerance of solid food) and lower (first bowel movement) GI recovery (GI-2). Time to discharge order written, postoperative LOS, postoperative ileus (POI)-related morbidity, opioid consumption, and adverse events (AEs) were evaluated. An independent adjudication of cardiovascular AEs was performed.

Results and limitations

Patients were randomized to alvimopan (n = 143) or placebo (n = 137); 277 patients were included in the modified intention-to-treat population. The alvimopan cohort experienced quicker GI-2 recovery (5.5 vs 6.8 d; hazard ratio: 1.8; p < 0.0001), shorter mean LOS (7.4 vs 10.1 d; p = 0.0051), and fewer episodes of POI-related morbidity (8.4% vs 29.1%; p < 0.001). The incidence of opioid consumption and AEs or serious AEs (SAEs) was comparable except for POI, which was lower in the alvimopan group (AEs: 7% vs 26%; SAEs: 5% vs 20%, respectively). Cardiovascular AEs occurred in 8.4% (alvimopan) and 15.3% (placebo) of patients (p = 0.09). Generalizability may be limited due to the exclusion of epidural analgesia and the inclusion of mostly high-volume centers utilizing open laparotomy.

Conclusions

Alvimopan is a useful addition to a standardized care pathway in patients undergoing RC by accelerating GI recovery and shortening LOS, with a safety profile similar to placebo.

Patient summary

This study examined the effects of alvimopan on bowel recovery in patients undergoing radical cystectomy for bladder cancer. Patients receiving alvimopan experienced quicker bowel recovery and had a shorter hospital stay compared with those who received placebo, with comparable safety.

Trial registration

ClinicalTrials.gov identifier NCT00708201     

An estimation of inguinal hernia epidemiology adjusted for population age structure in Tanzania

Purpose

Surgical conditions represent a significant source of global disease burden. Little is known about the epidemiology of inguinal hernia in resource-poor settings. We present a method to estimate inguinal hernia disease burden in Tanzania.

Methods

Using data from the United States National Health and Nutrition Examination Survey (NHANES) prospective cohort study and Tanzanian demographic figures, we calculated inguinal hernia incidence and prevalence in Tanzanian adults under three surgical rate scenarios. Gender-specific incidence figures from NHANES data were adjusted according to Tanzanian population age structure. Hernia duration was adjusted for Tanzanian life expectancy within each age group.

Results

The prevalence of inguinal hernia in Tanzanian adults is 5.36 % while an estimated 12.09 % of men had hernias. Today, 683,904 adults suffer from symptomatic inguinal hernia in Tanzania. The annual incidence of symptomatic hernias in Tanzanian adults is 163 per 100,000 population. At Tanzania’s current hernia repair rate, a backlog of 995,874 hernias in need of repair will develop over 10 years. 4.4 million disability-adjusted life-years would be averted with repair of prevalent symptomatic hernias in Tanzania.

Conclusions

Our data indicate the extent of inguinal hernia disease burden in Tanzania. By adjusting our figures for the age structure of Tanzania, we have demonstrated that while the incidence of symptomatic cases may be lower than previously thought, prevalence of inguinal hernia in Tanzania remains high. This approach provides an update to our previously described methodology for calculation of inguinal hernia epidemiology in resource-poor settings that may be used in multiple country contexts.     

Long-Term and Oncologic Outcomes of Robotic Versus Laparoscopic Liver Resection for Metastatic Colorectal Cancer: A Multicenter,Propensity Score Matching Analysis

World Journal of Surgery - To assess long-term oncologic outcomes of robotic-assisted liver resection (RLR) for colorectal cancer (CRC) metastases as compared to a propensity-matched cohort of...