A comparison of observational studies and randomized, controlled trials

Cardiometabolic Morbidity in Adults With Cerebral Palsy and Spina Bifida

PURPOSE

The purpose of this study was to compare the incidence of, and adjusted hazards for, cardiometabolic morbidities among adults with and without cerebral palsy or spina bifida.

METHODS

Privately insured beneficiaries were included if they had an International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnostic code for cerebral palsy or spina bifida (n = 15,302). Adults without cerebral palsy or spina bifida were also included (n = 1,935,480). Incidence estimates of common cardiometabolic morbidities were compared at 4 years of enrollment. Survival models were used to quantify unadjusted and adjusted hazard ratios (HRs) for incident cardiometabolic morbidities.

RESULTS

Adults living with cerebral palsy or spina bifida had a higher 4-year incidence of any cardiometabolic morbidity (41.5% vs 30.6%) as compared to adults without cerebral palsy or spina bifida, and differences were to a clinically meaningful extent. Fully adjusted survival models demonstrated that adults with cerebral palsy or spina bifida had a greater hazard for any cardiometabolic morbidity (HR: 1.52; 95% confidence interval [CI]: 1.47, 1.57), and all but 1 cardiometabolic disorder (nonalcoholic fatty liver disease) and ranged from HR: 1.20 (1.15, 1.25) for hypercholesterolemia to HR: 1.86 (1.74, 1.98) for heart failure.

CONCLUSIONS

Adults with cerebral palsy or spina bifida have a significantly higher incidence of, and risk for, common cardiometabolic morbidities, as compared to adults without cerebral palsy or spina bifida. Efforts are needed to facilitate the development of improved clinical screening algorithms and early interventions to reduce risk of cardiometabolic disease onset and progression in these higher-risk populations.

Hydromorphone versus morphine: a historical cohort study to evaluate the quality of postoperative analgesia

PURPOSE

Opioids are the most widely used therapy for pain during the postoperative period. It has been suggested by some that hydromorphone is clinically superior. Our primary objective was to determine if there is a difference in postoperative pain score ratings between adult patients receiving intravenous hydromorphone vs intravenous morphine on discharge from the post-anesthesia care unit (PACU).

METHODS

For this historical cohort study, convenience sampling was used to identify the first 605 patients ≥ 18 yr undergoing elective, non-cardiac surgery. Patients were categorized based on treatment in the PACU with hydromorphone (n = 326) or morphine (n = 279). Pain scores (scale of 0-10), nausea/vomiting (scale of 0-3), pruritis (scale of 0-3), and sedation (scale of 0-4), as well as total opioid dose administered from arrival in the PACU until readiness to discharge were evaluated.

RESULTS

For the primary outcome of pain reported at discharge from the PACU, there was no significant difference between the mean (standard deviation) hydromorphone numeric rating scale (NRS) [2.8 (1.6)] and the morphine NRS [2.5 (1.5)] after adjusting for potential confounders (adjusted mean difference, 0.10; 95% confidence interval, -0.21 to 0.42; P = 0.53). Similarly, there were no significant between-group differences in length of stay in the PACU, satisfactory analgesia, nausea/vomiting, and sedation.

CONCLUSION

This study serves to help guide the decision-making process for selecting either morphine or hydromorphone for acute postoperative analgesia. Overall, we found no significant difference for analgesia or for common opioid-related adverse effects between these two opioids in the postoperative period at the time of discharge from the PACU. Furthermore, according to this data, the equipotency ratio of hydromorphone to morphine is closer to 1:6.5 rather than the commonly employed 1:5 ratio.

Laparoscopic versus open distal gastrectomy for advanced gastric cancer: A meta-analysis of randomized controlled trials and high-quality nonrandomized comparative studies

BACKGROUND

Controversy persists about the effects of laparoscopic distal gastrectomy (LDG) versus open distal gastrectomy (ODG) on short-term surgical outcomes and long-term survival within the field of advanced gastric cancer (AGC).

METHODS

Studies published from January 1994 to February 2020 that compare LDG and ODG for AGC were identified. All randomized controlled trials (RCTs) were included. The selection of high-quality nonrandomized comparative studies (NRCTs) was based on a validated tool (Methodological Index for Nonrandomized Studies, MINORS). The short- and long-term outcomes of both procedures were compared.

RESULTS

Overall, 30 studies were included in this meta-analysis, which comprised of 8 RCTs and 22 NRCTs involving 16,029 patients (7864 LDGs, 8165 ODGs). The recurrence, 3-year disease-free survival (DFS), 3-year overall survival (OS), and 5-year OS rates for LDG and ODG were comparable. LDG was associated with a lower postoperative complication rate (OR 0.79; P < 0.00001), lower estimated volume of blood loss (WMD -102.21 mL; P < 0.00001), shorter postoperative hospital stay (WMD -1.96 days; P < 0.0001), shorter time to first flatus (WMD -0.54 day; P = 0.0007) and shorter time to first liquid diet (WMD -0.66 day; P = 0.001). The number of lymph nodes retrieved, mortality, intraoperative complications, intraoperative blood transfusion, and time to ambulation were similar. However, LDG was associated with a longer surgical time (WMD 33.57 min; P < 0.00001).

CONCLUSIONS

LDG with D2 lymphadenectomy is a safe and effective technique for patients with AGC when performed by experienced surgeons at high-volume specialized centers.

ECCDIA: an interactive web tool for the comprehensive analysis of clinical and survival data of esophageal cancer patients

BACKGROUND

Esophageal cancer (EC) is considered as one of the deadliest malignancies with respect to incidence and mortality rate, and numerous risk factors may affect the prognosis of EC patients. For better understanding of the risk factors associated with the onset and prognosis of this malignancy, we develop an interactive web-based tool for the convenient analysis of clinical and survival characteristics of EC patients.

METHODS

The clinical data were obtained from The Surveillance, Epidemiology, and End Results (SEER) database. Seven analysis and visualization modules were built with Shiny.

RESULTS

The Esophageal Cancer Clinical Data Interactive Analysis (ECCDIA, http://webapps.3steps.cn/ECCDIA/ ) was developed to provide basic data analysis, visualization, survival analysis, and nomogram of the overall group and subgroups of 77,273 EC patients recorded in SEER. The basic data analysis modules contained distribution analysis of clinical factor ratios, Sankey plot analysis for relationships between clinical factors, and a map for visualizing the distribution of clinical factors. The survival analysis included Kaplan-Meier (K-M) analysis and Cox analysis for different subgroups of EC patients. The nomogram module enabled clinicians to precisely predict the survival probability of different subgroups of EC patients.

CONCLUSION

ECCDIA provides clinicians with an interactive prediction and visualization tool for visualizing invaluable clinical and prognostic information of individual EC patients, further providing useful information for better understanding of esophageal cancer.

Do proton pump inhibitors increase mortality? A systematic review and in-depth analysis of the evidence

Proton pump inhibitors (PPIs) were primarily approved for short-term use (2 to 8 weeks). However, PPI use continues to expand. Widely believed to be safe, we reviewed emerging evidence on increased mortality with PPI long-term use. Our 2016 systematic PPI drug class review found that mortality was not reported as an outcome in randomized controlled trials (RCTs) that directly compared different PPIs. We sought more recent and comprehensive data on PPI harm outcomes from research syntheses as a follow-on. A search was conducted from January 2014 to January 2020. We searched MEDLINE, EMBASE, and Cochrane Central for evidence from systematic reviews (SRs) and primary studies reporting all-cause mortality in adults treated with a PPI for any indication (duration >12 weeks) compared to patients without PPI treatment (no use, placebo, or H2RA use). Two independent investigators assessed study eligibility, synthesized evidence, and assessed the quality of the included studies. Data on all-cause mortality were sought, analyzed, critically examined, and interpreted herein. From 1304 articles, one SR was identified that reported on all-cause mortality. The SRs pooled three observational studies with data to 1 year: odds ratio, 95% confidence interval (CI) 1.53-1.84. A RCT, the COMPASS (Cardiovascular Outcomes for People Using Anticoagulant Strategies) RCT with data to 3 years: hazard ratio (HR) 1.03, 95% CI 0.92-1.15. The US Veterans Affairs cohort study using a large national dataset with data to 10 years found a HR of 1.17, 95% CI (1.10-1.24) and (NNH) of 22. The most common causes of death were from cardiovascular and chronic kidney diseases, with an excess death of 15 and 4 per 1000 patients, respectively, over the 10-year period. Harms arising from real-world medication use are best evaluated using a pharmacovigilance "convergence of proof" approach using data from a variety of sources and various study designs. Given that most PPI indications for use recommended a treatment duration of less than 12 weeks, it seems clear that PPIs were significantly overused in older patients. The median exposure time to PPI ranged from 1 to 4.6 years. Signals of serious harms including increased mortality with long-term PPI use are reported in observational studies. The COMPASS trial findings are not inconsistent with contemporaneous findings from observational studies. The COMPASS RCT was unlikely to detect an increase in mortality given the trial was not powered to detect this outcome. The potential increase in mortality in older patients associated with prolonged PPI exposure needs to be conveyed to health professionals. Clinicians and patients may be able to reverse the relentless expansion of long-term PPI exposure by reviewing indications and considering potential harms as well as benefits.

Well-designed retrospective study versus small-sample prospective study in research based on laparoscopic and open radical distal gastrectomy for advanced gastric cancer

BACKGROUND

Well-designed retrospective studies (RSs) and small-sample prospective studies (PSs) evaluating the efficacy of interventions have received much attention. This study was designed to evaluate the differences between well-designed RSs and small-sample randomized controlled trials based on the efficacy of laparoscopic distal gastrectomy (LDG) and open distal gastrectomy (ODG) for advanced gastric cancer (GC).

METHODS

The clinicopathological data of 1360 patients with GC who underwent DG were analysed. After propensity score matching (1:1), 380 cases (ODG = 190, LDG = 190) were finally selected in a RS. Meanwhile, data from 120 patients (ODG = 60, LDG = 60) who enrolled in a PS were analysed.

RESULTS

In the PS, the LDG group had less intraoperative blood loss, shorter time to first flatus, and shorter time to fluid diet than the ODG group. In the RS, the LDG group had less intraoperative blood loss, and a shorter postoperative hospital stay than the ODG group. In the PS, the 3-year overall survival (OS) rate was 83.3% in the LDG group and 83.2% in the ODG group (p = 0.877). In the RS, the 3-year OS rate was 68.7% in the LDG group and 66.6% in the ODG group (p = 0.752). No significant interactions were observed between the two groups and any of the variables examined, either in the PS or RS. The recurrence patterns were similar in the two groups. Furthermore, Cox regression analysis showed that surgical method (LDG/ODG) was not a prognostic factor affecting OS or DFS, either prospectively or retrospectively.

CONCLUSIONS

The oncologic efficacy of laparoscopic and open distal gastrectomy for advanced GC is comparable. Well-designed RSs can be similar to small sample of PSs in assessing long-term oncologic outcomes of surgical interventions, but the short-term outcomes obtained should be treated with caution.

Empirical use of causal inference methods to evaluate survival differences in a real-world registry vs those found in randomized clinical trials

With heighted interest in causal inference based on real-world evidence, this empirical study sought to understand differences between the results of observational analyses and long-term randomized clinical trials. We hypothesized that patients deemed "eligible" for clinical trials would follow a different survival trajectory from those deemed "ineligible" and that this factor could partially explain results. In a large observational registry dataset, we estimated separate survival trajectories for hypothetically trial-eligible vs ineligible patients under both coronary artery bypass surgery (CABG) and percutaneous coronary intervention (PCI). We also explored whether results would depend on the causal inference method (inverse probability of treatment weighting vs optimal full propensity matching) or the approach to combine propensity scores from multiple imputations (the "across" vs "within" approaches). We found that, in this registry population of PCI/CABG multivessel patients, 32.5% would have been eligible for contemporaneous RCTs, suggesting that RCTs enroll selected populations. Additionally, we found treatment selection bias with different distributions of propensity scores between PCI and CABG patients. The different methodological approaches did not result in different conclusions. Overall, trial-eligible patients appeared to demonstrate at least marginally better survival than ineligible patients. Treatment comparisons by eligibility depended on disease severity. Among trial-eligible three-vessel diseased and trial-ineligible two-vessel diseased patients, CABG appeared to have at least a slight advantage with no treatment difference otherwise. In conclusion, our analyses suggest that RCTs enroll highly selected populations, and our findings are generally consistent with RCTs but less pronounced than major registry findings.

Regression of the Left Ventricular Hypertrophy in Patients with Essential Hypertension on Standard Drug Therapy

 PURPOSE: The American College of Cardiology/ American Heart Association 2017 and European Society of Cardiology/European Society of Hypertension 2018 guidelines were a paradigm shift in hypertension management in contemporary medicine. Lowering of blood pressure to less than 130 (systolic) and 80 (diastolic) mm of Hg irrespective of cardiovascular risk is recommended. While intensive blood pressure control is commonly achievable with rational pharmacotherapy, the magnitude of left ventricular hypertrophy regression is an independent factor in improvement in cardiovascular health. The regression of left ventricular hypertrophy has been adjudged as a clinically useful surrogate marker that reflects the efficacy of hypertension treatment. Though angiotensin converting enzyme inhibitors/ angiotensin receptor blockers (ACEI/ARB) are the preferred initial drug for greater regression of left ventricular mass, the choice of add-on therapy, if required, is still debatable. Therefore, in our observational study, we sought to compare the reduction in left ventricular mass index in hypertensives with left ventricular hypertrophy on standard ACEI/ARB based drug therapy.  MATERIALS AND METHODS: The cohort (n=217) comprised of patients with uncontrolled hypertension (blood pressure>140/90 mm of Hg) and left ventricular hypertrophy (left ventricular mass index>115 and 95 gram/square meter in males and females respectively). The add-on drug in ACEI/ARB therapy was either thiazide diuretics (TD) or calcium channel blockers (CCB). Four sub-cohorts were constituted: mono-therapy - group A (n=70, ACEI/ARB), dual-therapy - group B (n=48, ACEI/ARB+TD) and  group C (n=51, ACEI/ ARB+CCB), triple therapy - group D (n=48, ACEI/ ARB+TD+CCB). Left ventricular mass index was determined using echocardiography at baseline and after 24 weeks of therapy.  RESULTS: There was no significant difference in baseline clinical or demographic variables between group B and group C. Baseline blood pressure and duration of hypertension was greater in group D compared to group A (P<0.001). The reduction in left ventricular mass index (mean ±SD) in the four groups (A to D) was 16.7±18.7, 21.0±20.8, 20.5±15.5  and 29.1±21.5 g/m2  respectively (D>A, P=0.011, B versus C, P=1.00). The corresponding change in blood pressure (systolic/diastolic) was 18.5±13.6/8.9±11.2, 27.5±19.2/12.2±9.3, 23.4±16.7/ 5.4±10.1, 26.6±19.5/10.7±12.8 mm of Hg respectively (systolic, B>A, P=0.027, D>A, P=0.048) (diastolic, B>C, P=0.013).  CONCLUSION: Anti-hypertensive treatment with angiotensin converting enzyme inhibitors/angiotensin receptor blockers-based therapy produced graded regression of left ventricular hypertrophy with monotherapy, dual therapy and triple therapy.  In dual therapy, add-on of either thiazide diuretics or calcium channel blockers to angiotensin converting enzyme inhibitors/angiotensin receptor blockers showed equal efficacy in regression of left ventricular hypertrophy independent of blood pressure reduction.

Meta-analysis of changes in the levels of catecholamines and blood pressure with continuous positive airway pressure therapy in obstructive sleep apnea

Stress from obstructive sleep apnea (OSA) stimulates catecholamine release consequently exacerbating hypertension. However, different studies have shown a conflicting impact of continuous positive airway pressure (CPAP) treatment in patients with OSA on catecholamine levels and blood pressure. We aimed to examine changes to catecholamine levels and blood pressure in response to CPAP treatment. We conducted a meta‐analysis of data published up to May 2020. The quality of the studies was evaluated using standard tools for assessing the risk of bias. Meta‐analysis was conducted using RevMan (v5.3) and expressed in standardized mean difference (SMD) for catecholamines and mean difference (MD) for systolic (SBP) and diastolic blood pressure (DBP). A total of 38 studies met our search criteria; they consisted of 14 randomized control trials (RCT) totaling 576 participants and 24 prospective cohort studies (PCS) of 547 participants. Mean age ranged between 41 and 62 year and body mass index between 27.2 and 35.1 kg/m². CPAP treatment reduced 24‐hour urinary noradrenaline levels both in RCT (SMD = −1.1; 95% confidence interval (CI): −1.63 to − 0.56) and in PCS (SMD = 0.38 (CI: 0.24 to 0.53). SBP was also reduced by CPAP treatment in RCT (4.8 mmHg; CI: 2.0‐7.7) and in PCS (7.5 mmHg; CI: 3.3‐11.7). DBP was similarly reduced (3.0 mmHg; CI: 1.4‐4.6) and in PCS (5.1 mmHg; CI: 2.3‐8.0). In conclusion, CPAP treatment in patients with OSA reduces catecholamine levels and blood pressure. This suggests that sympathetic activity plays an intermediary role in hypertension associated with OSA‐related stress.

Influence of Renin-Angiotensin System Inhibitors on Lower-Respiratory Tract Infections in Type 2 Diabetes: The Fremantle Diabetes Study Phase II

OBJECTIVE

To determine whether ACE inhibitors (ACEi) and angiotensin receptor blockers (ARB) protect against lower-respiratory tract infections complicating type 2 diabetes.

RESEARCH DESIGN AND METHODS

Of 1,732 participants with diabetes recruited to the longitudinal observational Fremantle Diabetes Study Phase II (FDS2) between 2008 and 2011, 1,482 had confirmed type 2 diabetes (mean age 65.8 years and median diabetes duration 9.0 years; 51.6% were male). All were followed for hospitalizations for or with, or deaths from, pneumonia/influenza, ascertained from validated administrative data linkage from study entry to end of 2016. Cox regression and competing risk regression were used to identify independent predictors of this outcome.

RESULTS

Two-thirds of participants (n = 982) were taking an ACEi and/or ARB at study entry (498 [33.6%] ACEi, 408 [27.5%] ARB, 76 [5.1%] both). During 9,511 person-years of follow-up (mean ± SD 6.4 ± 2.0 years), 174 participants had incident pneumonia/influenza (156 hospitalizations and 18 deaths without hospitalization). In Cox regression analysis, baseline ACEi/ARB use was independently associated with a reduced risk of incident pneumonia/influenza (cause-specific hazard ratio [HR] 0.64 [95% CI 0.45, 0.89], P = 0.008). Allowing for the competing risk of death did not change this finding (subdistribution HR 0.67 [0.48, 0.95], P = 0.024), and similar reductions were seen for ACEi, ARB alone, and ACEi/ARB combination therapy. There was no significant change in use of ACEi/ARB during follow-up [interaction with ln(time), P = 0.70]. Other significant predictors of incident pneumonia/influenza were previously reported, clinically plausible variables.

CONCLUSIONS

ACEi/ARB reduce the risk of pneumonia/influenza in people with type 2 diabetes.

Study Design in Neurosurgical Research: Considerations for Observational and Experimental Cohort Studies

There is inadequate neurosurgical literature discussing appropriate clinical study design. Here, we explore considerations for 2 fundamental study designs of epidemiology: experimental and observational cohort studies, through examples of theoretical yet realistic neurosurgical research questions. By examining 2 common neurosurgical procedures-namely, subdural drains for evacuation of chronic subdural hematoma, and the utility of navigation for placing external ventricular drains-we characterize the framework of cohort study models for clinical research applications.

Safety of intraoperative hypothermia for patients: meta-analyses of randomized controlled trials and observational studies

BACKGROUND

Previous studies have shown that intraoperative hypothermia was associated with higher risks of clinical adverse events, but we found otherwise from recent evidences. This study aims to synthesize the existing evidence evaluating safety of intraoperative hypothermia.

METHODS

Articles, reviews, ongoing trials and grey literatures were retrieved from PubMed, The Cochrane Library, Clinical Trails and CNKI (a Chinese national database) till February 2nd, 2019. Both randomized controlled trials and observational studies compared incidences of all sorts of intra- and post-operative consequences between hypothermia and normothermia were included. Researches comparing different warming systems were excluded. We also examined risks of hypothermia using lowered standards (35.5 °C and 35 °C) from a Chinese trial (ChiCTR-IPR-17011099).

RESULTS

A total of 9 RCT studies and 11 observational studies were included. RCT-synthesized results showed that intraoperative hypothermia was associated with higher risks of bleeding (MD = 131.90, 95%CI: 117.42, 146.38), surgical site infection (RD = 0.14, 95%CI: 0.06, 0.21) and shivering (RD = 0.32, 95%CI: 0.06, 0.58) but with no significant differences in duration of surgery, hospital stay or mortality. Observational study-synthesized evidences showed that intraoperative hypothermia did not result in higher risks in any of these adverse events. Results didn't change even if the standard of hypothermia was lowered by 0.5-1.0 °C.

CONCLUSIONS

The study indicates that the synthesized risks resulted by intra-operative hypothermia might be overestimated and the eligibility of 36 °C to define hypothermia is not sensitive enough. Given body-temperature protection has not been popularized in China, it is still critical to normalize the hypothermia prevention at this stage.

Trends in the level of evidence and impact of clinical studies published in leading oral implantology journals: 2008-2018

OBJECTIVES

To present the characteristics and level of evidence (LOE) of clinical studies published in leading oral implantology journals during 2008-2018 and to explore whether the LOE of a study is associated with its scientific and social impact.

MATERIALS AND METHODS

Clinical studies with direct relevance to the evaluation of healthcare interventions published in 2008, 2013, and 2018 in six oral implantology journals were identified via hand searches. A modified 4-level Oxford 2011 LOE tool was used to assess the LOE of all eligible studies. The citation count and Altmetric Attention Score (AAS) of each study were extracted from Web of Science and Altmetric Explorer, respectively. Thereafter, multivariable generalized estimation equation analyses were used to investigate the association between LOE, citation counts, and AAS, adjusting for potential confounding factors and clustering effects.

RESULTS

A total of 763 clinical studies were included, among which the proportion of level-1, level-2, level-3, and level-4 studies was 2.4%, 30.4%, 40.2%, and 27.0%, respectively. During 2008-2018, the proportion of high LOE studies (level-1 and level-2) increased substantially from 24.6% to 43.1%, although the number of systematic reviews that only include randomized controlled trials has remained limited. According to multivariable analyses, the citation count (p = .002) and AAS (p = .005) of high LOE studies were both significantly greater than those of low LOE studies.

CONCLUSIONS

During the past decade, the proportion of high LOE studies has increased substantially in the field of oral implantology. Clinical studies with higher LOE tend to have greater scientific and social impact.

Survival Advantage of Laparoscopic Versus Open Resection For Colorectal Liver Metastases: A Meta-analysis of Individual Patient Data From Randomized Trials and Propensity-score Matched Studies

OBJECTIVE

To perform an individual participant data meta-analysis using randomized trials and propensity-score matched (PSM) studies which compared laparoscopic versus open hepatectomy for patients with colorectal liver metastases (CLM).

BACKGROUND

Randomized trials and PSM studies constitute the highest level of evidence in addressing the long-term oncologic efficacy of laparoscopic versus open resection for CLM. However, individual studies are limited by the reporting of overall survival in ways not amenable to traditional methods of meta-analysis, and violation of the proportional hazards assumption.

METHODS

Survival information of individual patients was reconstructed from the published Kaplan-Meier curves with the aid of a computer vision program. Frequentist and Bayesian survival models (taking into account random-effects and nonproportional hazards) were fitted to compare overall survival of patients who underwent laparoscopic versus open surgery. To handle long plateaus in the tails of survival curves, we also exploited "cure models" to estimate the fraction of patients effectively "cured" of disease.

RESULTS

Individual patient data from 2 randomized trials and 13 PSM studies involving 3148 participants were reconstructed. Laparoscopic resection was associated with a lower hazard rate of death (stratified hazard ratio = 0.853, 95% confidence interval: 0.754-0.965, P = 0.0114), and there was evidence of time-varying effects (P = 0.0324) in which the magnitude of hazard ratios increased over time. The fractions of long-term cancer survivors were estimated to be 47.4% and 18.0% in the laparoscopy and open surgery groups, respectively. At 10-year follow-up, the restricted mean survival time was 8.6 months (or 12.1%) longer in the laparoscopy arm (P < 0.0001). In a subgroup analysis, elderly patients (≥65 years old) treated with laparoscopy experienced longer 3-year average life expectancy (+6.2%, P = 0.018), and those who live past the 5-year milestone (46.1%) seem to be cured of disease.

CONCLUSIONS

This patient-level meta-analysis of high-quality studies demonstrated an unexpected survival benefit in favor of laparoscopic over open resection for CLM in the long-term. From a conservative viewpoint, these results can be interpreted to indicate that laparoscopy is at least not inferior to the standard open approach.

Some statistical memes which sound correct but aren't quite: Application to the analysis of observational databases used in learning health systems

We consider four memes, correct within the context of randomized trials but requiring modification for the analysis of the observational databases typically associated with learning health systems: (a) the right answer always requires randomization; (b) a bigger database is always a better database; (c) statistical adjustment always works if based on a large enough database; and (d) always make a formal adjustment when testing multiple hypotheses. The rationale for these memes within the context of randomized trials is discussed, and the memes are restated in a fashion that is consistent with learning health systems.

Evaluation of the Use of Cancer Registry Data for Comparative Effectiveness Research

Importance

Researchers often analyze cancer registry data to assess for differences in survival among cancer treatments. However, the retrospective, nonrandomized design of these analyses raises questions about study validity.

Objective

To examine the extent to which comparative effectiveness analyses using observational cancer registry data produce results concordant with those of randomized clinical trials.

Design, Setting, and Participants

In this comparative effectiveness study, a total of 141 randomized clinical trials referenced in the National Comprehensive Cancer Network Clinical Practice Guidelines for 8 common solid tumor types were identified. Data on participants within the National Cancer Database (NCDB) diagnosed between 2004 and 2014, matching the eligibility criteria of the randomized clinical trial, were obtained. The present study was conducted from August 1, 2017, to September 10, 2019. The trials included 85 118 patients, and the corresponding NCDB analyses included 1 344 536 patients. Three Cox proportional hazards regression models were used to determine hazard ratios (HRs) for overall survival, including univariable, multivariable, and propensity score-adjusted models. Multivariable and propensity score analyses controlled for potential confounders, including demographic, comorbidity, clinical, treatment, and tumor-related variables.

Main Outcomes and Measures

The main outcome was concordance between the results of randomized clinical trials and observational cancer registry data. Hazard ratios with an NCDB analysis were considered concordant if the NDCB HR fell within the 95% CI of the randomized clinical trial HR. An NCDB analysis was considered concordant if both the NCDB and clinical trial P values for survival were nonsignificant (P ≥ .05) or if they were both significant (P < .05) with survival favoring the same treatment arm in the NCDB and in the randomized clinical trial.

Results

Analyses using the NCDB-produced HRs for survival were concordant with those of 141 randomized clinical trials in 79 univariable analyses (56%), 98 multivariable analyses (70%), and 90 propensity score models (64%). The NCDB analyses produced P values concordant with randomized clinical trials in 58 univariable analyses (41%), 65 multivariable analyses (46%), and 63 propensity score models (45%). No clinical trial characteristics were associated with concordance between NCDB analyses and randomized clinical trials, including disease site, type of clinical intervention, or severity of cancer.

Conclusions and Relevance

The findings of this study suggest that comparative effectiveness research using cancer registry data often produces survival outcomes discordant with those of randomized clinical trial data. These findings may help provide context for clinicians and policy makers interpreting observational comparative effectiveness research in oncology.

Conservative vs. operative treatment for humeral shaft fractures: a meta-analysis and systematic review of randomized clinical trials and observational studies

BACKGROUND

This meta-analysis aimed to compare conservative vs. operative treatment for humeral shaft fractures in terms of the nonunion rate, reintervention rate, permanent radial nerve palsy rate, and functional outcomes. Secondarily, effect estimates from observational studies were compared with estimates of randomized clinical trials (RCTs).

METHODS

The PubMed/Medline, Embase, CENTRAL (Cochrane Central Register of Controlled Trials), and CINAHL (Cumulative Index to Nursing and Allied Health Literature) databases were searched for both RCTs and observational studies comparing conservative with operative treatment for humeral shaft fractures.

RESULTS

A total of 2 RCTs (150 patients) and 10 observational studies (1262 patients) were included. The pooled nonunion rate of all studies was higher in patients treated conservatively (15.3%) vs. operatively (6.4%) (risk difference, 8%; odds ratio [OR], 2.9; 95% confidence interval [CI], 1.8-4.5; I² = 0%). The reintervention rate was also higher for conservative treatment (14.3%) than for operative treatment (8.9%) (risk difference, 6%; OR, 1.9; 95% CI, 1.1-3.5; I² = 30%). The higher reintervention rate was predominantly attributable to the higher nonunion rate in patients treated conservatively. The permanent radial nerve palsy rate was equal in both groups (OR, 0.6; 95% CI, 0.2-1.9; I² = 18%). There appeared to be no difference in mean time to union and mean Disabilities of the Arm, Shoulder and Hand scores between the treatment groups. No difference was found between effect estimates form observational studies and RCTs.

CONCLUSION

This systematic review shows that satisfactory results can be achieved with both conservative and operative management; however, operative treatment reduces the risk of nonunion compared with conservative treatment, with comparable reintervention rates (for indications other than nonunion). Furthermore, operative treatment results in a similar permanent radial nerve palsy rate, despite its inherent additional surgery-related risks. No difference in mean time-to-union and short-term functional results was detected.

Associations of Bariatric Interventions With Micronutrient and Endocrine Disturbances

IMPORTANCE

Few studies have described the longitudinal trajectories of serum levels of micronutrients whose deficiencies are associated with serious sequelae following bariatric procedures, such as anemia, osteoporotic fractures, and neuropathies. Furthermore, previous studies comparing laparoscopic sleeve gastrectomy (LSG) vs Roux-en-Y gastric bypass (LRYGB) or one-anastomosis gastric bypass (OAGB) procedures may have been limited by selection and confounding biases.

OBJECTIVE

To appraise the spectrum and temporal course of micronutrient deficiencies associated with bone metabolism and erythropoiesis after LSG vs OAGB or LRYGB procedures, using the propensity score as a balancing score.

DESIGN, SETTING, AND PARTICIPANTS

This prospective, longitudinal comparative effectiveness study was conducted at a high-volume bariatric unit in Singapore from September 1, 2008, to November 30, 2017, with a cutoff date for analysis of September 2018. Patients who underwent adjustable gastric banding, biliopancreatic diversion procedures, and intragastric balloon procedures were excluded. All other patients who underwent bariatric procedures were included. Data were analyzed from September 23 to 30, 2018.

MAIN OUTCOMES AND MEASURES

Serial assessment of 13 biochemical parameters at 12 time points for up to 5 years after bariatric procedure. Inverse probability-of-treatment weights were used to obtain estimates of the mean associations of variables assessed with the bariatric surgical interventions. Longitudinal trajectories were analyzed using mixed-effects generalized linear models to apportion the temporal variation of serum micronutrients into fixed-effects and random-effects components.

RESULTS

A total of 688 patients were included in this study, of whom 499 underwent LSG (mean [SD] age, 41.5 [11.3] years; 318 [63.7%] women) and 189 underwent OAGB or LRYGB (mean [SD] age, 48.6 [9.4] years; 112 [59.3%] women). There were no differences during follow-up among patients who underwent LSG vs those who underwent OAGB or LRYGB in intact parathyroid hormone levels (mean difference, 7.05 [95% CI, -28.67 to 42.77] pg/mL; P = .70), serum 25-hydroxyvitamin D levels (mean difference, -0.72 [95% CI, -1.56 to 0.12] ng/mL; P = .09), or phosphate levels (mean difference, 0.006 [95% CI, -0.052 to 0.064] mg/dL; P = .83). Hemoglobin levels were a mean 0.63 (95% CI, 0.41 to 0.85) g/dL higher among patients who underwent LSG compared with those who underwent OAGB or LRYGB (P < .001), despite no differences in iron concentration levels (mean difference, 1.50 [95% CI, -1.39 to 4.39] µg/dL; P = .31), total iron-binding capacity (mean difference, 4.36 [95% CI, -5.25 to 13.98] µg/dL; P = .37), or ferritin levels (mean difference, 3.0 [95% CI, -13.0 to 18.9] ng/mL; P = .71). Compared with patients who underwent LSG procedures, patients who underwent OAGB or LRYGB had higher folate levels (mean difference, 2.376 [95% CI, 1.716 to 3.036] ng/mL; P < .001) but lower serum magnesium levels (mean difference, -0.25 [95% CI, -0.35 to -0.16] mg/dL; P < .001) and zinc levels (mean difference, -7.58 [95% CI, -9.92 to -5.24] µg/dL; P < .001).

CONCLUSIONS AND RELEVANCE

These findings suggest that LSG vs OAGB or LRYGB procedures have differential associations with various micronutrient and metabolic parameters. These differences should be recognized in guidelines for postbariatric nutritional surveillance and prevention.

Effect of Body Mass Index on Postoperative Nausea and Vomiting: Propensity Analysis

The impact of body mass index (BMI) on postoperative nausea and vomiting (PONV) is controversial, and few studies have focused on their relationship. We investigated the effects of BMI on PONV, taking into account other PONV risk factors. We analyzed adults over the age of 18 years who received general anesthesia between 2015 and 2019, using propensity score matching. Before propensity score matching, odds ratios (ORs) for PONV were lower for overweight (OR, 0.91; 95% confidence interval (CI), 0.87–0.96; p < 0.0001) or obese patients (OR, 0.77; 95% CI, 0.71–0.84; p < 0.0001) than for normal-BMI patients. After matching, the ORs for PONV of overweight (OR, 0.89; 95% CI, 0.80–0.98; p = 0.016) and obese patients (OR, 0.71; 95% CI, 0.63–0.79; p < 0.0001) were low. However, the ORs of underweight patients did not differ from those of normal-BMI patients, irrespective of matching. Therefore, the incidence of PONV may be lower among adults with a higher-than-normal BMI.

Radical radiotherapy for prostate cancer: patterns of care in Sweden 1998-2016

Introduction: Radiotherapy is an established treatment option for prostate cancer (PCa), both as primary treatment and secondary treatment after radical prostatectomy (RP). Since 1998, detailed data on radiotherapy delivered to Swedish men with PCa (e.g. treatment modalities, absorbed doses, fractionation) have been collated within PCa data Base Sweden (PCBaSe). This study reports patterns of radical radiotherapy for PCa in Sweden over the past two decades.Materials and methods: All men with non-metastatic PCa (1998-2016) who received external beam radiotherapy (EBRT) or high or low dose-rate brachytherapy (HDR-BT/LDR-BT) were identified in PCBaSe. Analyses included: trends in radiation techniques, fractionation patterns and total doses over time; PCa-specific survival comparing treatment in 2007-2017 with 1998-2006; and regional variation in type of primary radiotherapy.Results: About 20,876 men underwent primary radiotherapy. The main treatment modalities include conventionally fractionated (2.0 Gy/fraction) EBRT (51%), EBRT with HDR-BT boost (27%) and hypofractionated (>2.4 Gy/fraction) EBRT (11%). EBRT with photon or proton boost and HDR-BT and LDR-BT monotherapies were each used minimally. Use of dose-escalated EBRT (>74 Gy) and moderate hypofractionation increased over time, while use of HDR-BT declined. Considerable regional variation in treatment modalities was apparent. Risk of PCa death following primary radiotherapy had declined for intermediate-risk (HR: 0.60; 95%CI 0.47-0.87) and high-risk PCa (HR: 0.72; 95%CI 0.61-0.86).Discussion: Increased use of dose escalation and hypofractionated EBRT has occurred in Sweden over the past two decades, reflecting current evidence and practice guidelines. Disease-specific outcomes have also improved. Data collected in PCBaSe provide an excellent resource for further research into RT use in PCa management.

Benchmarking Observational Analyses Against Randomized Trials: a Review of Studies Assessing Propensity Score Methods

BACKGROUND

Observational analysis methods can be refined by benchmarking against randomized trials. We reviewed studies systematically comparing observational analyses using propensity score methods against randomized trials to explore whether intervention or outcome characteristics predict agreement between designs.

METHODS

We searched PubMed (from January 1, 2000, to April 30, 2017), the AHRQ Scientific Resource Center Methods Library, reference lists, and bibliographies to identify systematic reviews that compared estimates from observational analyses using propensity scores against randomized trials across three or more clinical topics; reported extractable relative risk (RR) data; and were published in English. One reviewer extracted data from all eligible systematic reviews; a second reviewer verified the extracted data.

RESULTS

Six systematic reviews matching published observational studies to randomized trials, published between 2012 and 2016, met our inclusion criteria. The reviews reported on 127 comparisons overall, in cardiology (29 comparisons), surgery (49), critical care medicine and sepsis (46), nephrology (2), and oncology (1). Disagreements were large (relative RR < 0.7 or > 1.43) in 68 (54%) and statistically significant in 12 (9%) of the comparisons. The degree of agreement varied among reviews but was not strongly associated with intervention or outcome characteristics.

DISCUSSION

Disagreements between observational studies using propensity score methods and randomized trials can occur for many reasons and the available data cannot be used to discern the reasons behind specific disagreements. Better benchmarking of observational analyses using propensity scores (and other causal inference methods) is possible using observational studies that explicitly attempt to emulate target trials.

Which study outcomes change practice

The use of evidence based medicine to guide treatment decision making is widely supported by clinicians as a method to improve patient care and outcomes. Surgeons and physicians play a key role in both the design of clinical and translational research studies, as well as the implementation of the results. With the massive volume of published studies, it is increasingly difficult for clinicians to evaluate the literature and appropriately integrate novel findings into practice. With a focus on research studies in the field of orthopaedic surgery, the purpose of this review is to discuss which factors lead to impactful conclusions and clinical change, including the role of outcome selection, study design, presentation of results, and stakeholder involvement.

Operative vs Nonoperative Treatment of Distal Radius Fractures in Adults: A Systematic Review and Meta-analysis

IMPORTANCE

No consensus has been reached to date regarding the optimal treatment for distal radius fractures. The international rate of operative treatment has been increasing, despite higher costs and limited functional outcome evidence to support this shift.

OBJECTIVES

To compare functional, clinical, and radiologic outcomes after operative vs nonoperative treatment of distal radius fractures in adults.

DATA SOURCES

The PubMed/MEDLINE, Embase, CENTRAL (Cochrane Central Register of Controlled Trials), and CINAHL (Cumulative Index to Nursing and Allied Health Literature) databases were searched from inception to June 15, 2019, for studies comparing operative vs nonoperative treatment of distal radius fractures.

STUDY SELECTION

Randomized clinical trials (RCTs) and observational studies reporting on the following: acute distal radius fracture with operative treatment (internal or external fixation) vs nonoperative treatment (cast immobilization, splinting, or bracing); patients 18 years or older; and functional outcome. Studies in a language other than English or reporting treatment for refracture were excluded.

DATA EXTRACTION AND SYNTHESIS

Data extraction was performed independently by 2 reviewers. Effect estimates were pooled using random-effects models and presented as risk ratios (RRs) or mean differences (MDs) with 95% CIs. Data were analyzed in September 2019.

MAIN OUTCOMES AND MEASURES

The primary outcome measures included medium-term functional outcome measured with the Disabilities of the Arm, Shoulder and Hand questionnaire (DASH) and the overall complication rate after operative and nonoperative treatment.

RESULTS

A total of 23 unique studies were included, consisting of 8 RCTs and 15 observational studies, that described 2254 unique patients. Among the studies that presented sex data, 1769 patients were women [80.6%]. Overall weighted mean age was 67 [range, 22-90] years). The RCTs included 656 patients (29.1%); observational studies, 1598 patients (70.9%). The overall pooled effect estimates the showed a significant improvement in medium-term (≤1 year) DASH score after operative treatment compared with nonoperative treatment (MD, -5.22 [95% CI, -8.87 to -1.57]; P = .005; I2 = 84%). No difference in complication rate was observed (RR, 1.03 [95% CI, 0.69-1.55]; P = .87; I2 = 62%). A significant improvement in grip strength was noted after operative treatment, measured in kilograms (MD, 2.73 [95% CI, 0.15-5.32]; P = .04; I2 = 79%) and as a percentage of the unaffected side (MD, 8.21 [95% CI, 2.26-14.15]; P = .007; I2 = 76%). No improvement in medium-term DASH score was found in the subgroup of studies that only included patients 60 years or older (MD, -0.98 [95% CI, -3.52 to 1.57]; P = .45; I2 = 34%]), compared with a larger improvement in medium-term DASH score after operative treatment in the other studies that included patients 18 years or older (MD, -7.50 [95% CI, -12.40 to -2.60]; P = .003; I2 = 77%); the difference between these subgroups was statically significant (test for subgroup differences, P = .02).

CONCLUSIONS AND RELEVANCE

This meta-analysis suggests that operative treatment of distal radius fractures improves the medium-term DASH score and grip strength compared with nonoperative treatment in adults, with no difference in overall complication rate. The findings suggest that operative treatment might be more effective and have a greater effect on the health and well-being of younger, nonelderly patients.

Emerging opportunities to harness real world data: An introduction to data sources, concepts, and applications

While randomized controlled trials (RCTs) are the gold standard for comparative effectiveness research, they are unable to provide the answers to all pertinent clinical and research questions. Real world evidence (RWE), that is, clinical evidence obtained outside RCTs and often through routine clinical practice, offers the potential to conduct observational studies that accelerate advances in care, improve outcomes for patients, and provide important insights that can answer important questions. Once appropriate information technology is available, real world data can be cost-effective to generate. RWE serves a vital role in the evaluation of treatment strategies for which there are no RCTs and for describing patterns of care. RWE also serves as an important adjunct to RCTs and can be used to determine if benefits seen in RCTs extend to clinical practice, provide insight into the findings of RCTs, generate hypotheses for future RCTs, and inform the design of future RCTs. These potential benefits must be balanced against some of the important limitations of RWE, including variable data quality, lack of granularity for important clinical variables, and the potential for bias and confounding. By using appropriate analytic techniques and study design, these limitations can be minimized but not eliminated. Going forward, RWE studies may be enhanced by using rigorous data quality standards, incorporating randomization, developing more prospective registries, and better leveraging data from electronic health records.

Effect of a Preoperative Proton Pump Inhibitor and Gastroesophageal Reflux Disease on Postoperative Nausea and Vomiting

Postoperative nausea and vomiting (PONV) are common complications after anesthesia, but no study has considered the effects of a proton pump inhibitor (PPI) and gastroesophageal reflux disease (GERD) on PONV at the same time. Thus, we investigated the effects of a PPI and GERD on PONV. Patients aged ≥18 years who underwent general anesthesia between 2010 and 2019 were enrolled. In total, 202,439 patients were included and 21,361 In a multivariate analysis, the OR for PONV was higher in subjects with GERD (OR, 1.157; 95% CI, 1.032-1.298; p = 0.012). The OR was lower for subjects with taking a PPI (OR, 0.890; 95% CI, 0.832-0.953; p < 0.0001). In patients without GERD, the incidence of PONV was lower when lansoprazole (OR, 0.801; 95% CI, 0.718-0.894; p < 0.0001), pantoprazole (OR, 0.856; 95% CI, 0.748-0.980; p = 0.025) and ilaprazole (OR, 0.391; 95% CI, 0.158-0.966; p = 0.042) were taken. However, in GERD patients, all PPIs did not show reducing the incidence of PONV. Taken together, the results show that a lansoprazole, pantoprazole, and ilaprazole reduced PONV in patients without GERD, and PPI could not reduce PONV in patients with GERD.

Effectiveness of Inferior Vena Cava Filters in Patients With Stable and Unstable Pulmonary Embolism and Trends in Their Use

BACKGROUND

Trends in the use of inferior vena cava (IVC) filters in patients with pulmonary embolism (PE) who are stratified according to whether they are stable or unstable (in shock or ventilator dependent) may show where improvements of management could be made according to the best evidence that we now have.

METHODS

This was a retrospective cohort study based on administrative data, 1999-2014, from the National (Nationwide) Inpatient Sample.

RESULTS

In-hospital all-cause mortality in unstable patients who received an IVC filter was lower in each year of investigation and in all age groups. Mortality from 1999 to 2014 was 10,140 of 35,230 (28.8%) with an IVC filter compared with 54,018 of 116,642 (46.3%) without a filter (P <0.0001). In stable patients from 1999 to 2014, mortality with an IVC filter was 31,909 of 546,858 (5.8%) with an IVC filter compared with 220,443 of 3,367,783 (6.5%) without a filter (P <0.0001). In patients ages > 80 years, mortality in stable patients with an IVC filter was 7,438 of 114,457 (6.5%) with an IVC filter compared with 64,113 of 567,348 (11.3%) without an IVC filter (P <0.0001). The number of stable patients who received an IVC filter decreased from 2010 to 2014, but even in those years the largest number of IVC filters was inserted in stable patients, 194,502 of 212,611 (91.5%).

CONCLUSIONS

Mortality is markedly reduced in unstable patients who receive an IVC filter. Despite this, the proportion of unstable patients who receive an IVC filter is decreasing. The largest number of IVC filters continues to be inserted in stable patients, although there is no evidence of a clinically meaningful reduced mortality with IVC filters in stable patients unless age >80 years.

Can a Successful Outcome After Surgery for Lumbar Disc Herniation Be Defined by the Oswestry Disability Index Raw Score?

STUDY DESIGN

Prospective multicenter cohort study.

OBJECTIVE

To investigate (1) the discriminative ability and cutoff estimates for success 12 months after surgery for lumbar disc herniation on the Oswestry Disability Index (ODI) raw score compared with a change and a percentage change score and (2) to what extent these clinical outcomes depend on the baseline disability.

METHODS

A total of 6840 patients operated for lumbar disc herniation from the Norwegian Registry for Spine Surgery (NORspine) were included. In receiver operating characteristic (ROC) curve analyses, a global perceived effect (GPE) scale (1-7) was used an external anchor. Success was defined as categories 1-2, "completely recovered" and "much better." Cutoffs for success for subgroups with different preoperative disability were also estimated.

RESULTS

When defining success after surgery for lumbar disc herniation, the accuracy (sensitivity, specificity, area under the curve, 95% CI) for the ODI raw score (0.83, 0.87, 0.930, 0.924-0.937) was comparable to the ODI percentage change score (0.85, 0.85, 0.925, 0.918-0.931), and higher than the ODI change score (0.79, 0.73, 0.838, 0.830-0.852). The cutoff for success was highly dependent on the amount of baseline disability (low-high), with cutoffs ranging from 13 to 28 for the ODI raw score and 39% to 66% for ODI percentage change. The ODI change score (points) was not as accurate.

CONCLUSION

The 12-month ODI raw score, like the ODI percentage change score, can define a successful outcome with excellent accuracy. Adjustment for the baseline ODI score should be performed when comparing outcomes across groups, and one should consider using cutoffs according to preoperative disability (low, medium, high ODI scores).

12th Roche Diabetes Care Network Meeting: April 11-13, 2019, Copenhagen, Denmark

A panel of international experts in the field of diabetes and diabetes technology met in Copenhagen, Denmark, for the 12th Roche Diabetes Care Network Meeting. The goal of these meetings is to share current knowledge, facilitate new collaborations, and encourage further research projects that can improve the lives of people with diabetes. Specific areas of interest included use of telemedicine and mobile health technologies, behavior change, patient-centered care, and multifactorial approaches to addressing all metabolic abnormalities associated with diabetes. The 2019 meeting covered a comprehensive scientific program and four keynote lectures.

Effect of the fixed combination of valerian, lemon balm, passionflower, and butterbur extracts (Ze 185) on the prescription pattern of benzodiazepines in hospitalized psychiatric patients-A retrospective case-control investigation

Stress is an increasing problem that can result in various psychiatric and somatoform symptoms. Among others, benzodiazepines and valerian preparations are used to treat stress symptoms. The aim of this study was to investigate whether the prescription of a fixed herbal extract combination of valerian, lemon balm, passionflower, and butterbur (Ze 185) changes the prescription pattern of benzodiazepines in hospitalized psychiatric patients. In a retrospective case‐control study, anonymized medical record data from 3,252 psychiatric in‐house patients were analysed over a 3.5‐year period. Cases (n = 1,548) with a prescription of Ze 185 and controls (n = 1,704) were matched by age, gender, hospitalization interval, and main International Classification of Diseases, Version 10 F‐diagnoses. The primary objective was to investigate the effect of Ze 185 on the prescription pattern of benzodiazepines. Secondary objectives investigated the prescriptions of concomitant drugs and effectiveness of the hospital stay. Distribution of drug classes was analysed using the WHO's anatomic‐therapeutic‐chemical code. Data showed that both treatment modalities had a comparable clinical effectiveness but with significantly less prescriptions of benzodiazepines in the Ze 185 group (p = .006). This is of clinical importance because suitable alternatives to benzodiazepines are desirable. To obtain more support for this hypothesis, a dedicated randomized, controlled clinical trial monitoring drug safety is required.

Prevalence, Incidence, and Risk Factors for Tinnitus

How many people are affected by tinnitus? Is the risk of developing tinnitus on the rise or has it been declining over time? What modifiable lifestyle factors could help to prevent tinnitus? These population-based questions can be addressed through epidemiological research. Epidemiology refers to the underlying and basic science of public health. It describes the study of the distribution and determinants of health-related states or events in specified populations and the application of this study to the control of health problems. There are two key concepts in epidemiology: (1) measures of frequency and (2) measures of effect. In this chapter, we introduce the two main measures of frequency, prevalence and incidence. We also introduce the notion of risk factors, critical for understanding measures of effect concerning the risk of developing a health condition. In both sections, we provide illustrative examples from the published literature on tinnitus. We end by offering a critical evaluation of the current status of epidemiological research on tinnitus and point to some promising future directions.

Heckman-type selection models to obtain unbiased estimates with missing measures outcome: theoretical considerations and an application to missing birth weight data

BACKGROUND

In low-income settings, key outcomes such as biomarkers or clinical assessments are often missing for a substantial proportion of the study population. The aim of this study was to assess the extent to which Heckman-type selection models can create unbiased estimates in such settings.

METHODS

We introduce the basic Heckman model in a first stage, and then use simulation models to compare the performance of the model to alternative approaches used in the literature for missing outcome data, including complete case analysis (CCA), multiple imputations by chained equations (MICE) and pattern imputation with delta adjustment (PIDA). Last, we use a large population-representative data set on antenatal supplementation (AS) and birth outcomes from Côte d'Ivoire to illustrate the empirical relevance of this method.

RESULTS

All models performed well when data were missing at random. When missingness in the outcome data was related to unobserved determinants of the outcome, large and systematic biases were found for CCA and MICE, while Heckman-style selection models yielded unbiased estimates. Using Heckman-type selection models to correct for missingness in our empirical application, we found supplementation effect sizes that were very close to those reported in the most recent systematic review of clinical AS trials.

CONCLUSION

Missingness in health outcome can lead to substantial bias. Heckman-selection models can correct for this selection bias and yield unbiased estimates, even when the proportion of missing data is substantial.

Association of Antidepressant Use With Adverse Health Outcomes: A Systematic Umbrella Review

IMPORTANCE

Antidepressant use is increasing worldwide. Yet, contrasting evidence on the safety of antidepressants is available from meta-analyses, and the credibility of these findings has not been quantified.

OBJECTIVE

To grade the evidence from published meta-analyses of observational studies that assessed the association between antidepressant use or exposure and adverse health outcomes.

DATA SOURCES

PubMed, Scopus, and PsycINFO were searched from database inception to April 5, 2019.

EVIDENCE REVIEW

Only meta-analyses of observational studies with a cohort or case-control study design were eligible. Two independent reviewers recorded the data and assessed the methodological quality of the included meta-analyses. Evidence of association was ranked according to established criteria as follows: convincing, highly suggestive, suggestive, weak, or not significant.

RESULTS

Forty-five meta-analyses (17.9%) from 4471 studies identified and 252 full-text articles scrutinized were selected that described 120 associations, including data from 1012 individual effect size estimates. Seventy-four (61.7%) of the 120 associations were nominally statistically significant at P ≤ .05 using random-effects models. Fifty-two associations (43.4%) had large heterogeneity (I2 > 50%), whereas small-study effects were found for 17 associations (14.2%) and excess significance bias was found for 9 associations (7.5%). Convincing evidence emerged from both main and sensitivity analyses for the association between antidepressant use and risk of suicide attempt or completion among children and adolescents, autism spectrum disorders with antidepressant exposure before and during pregnancy, preterm birth, and low Apgar scores. None of these associations remained supported by convincing evidence after sensitivity analysis, which adjusted for confounding by indication.

CONCLUSIONS AND RELEVANCE

This study's findings suggest that most putative adverse health outcomes associated with antidepressant use may not be supported by convincing evidence, and confounding by indication may alter the few associations with convincing evidence. Antidepressant use appears to be safe for the treatment of psychiatric disorders, but more studies matching for underlying disease are needed to clarify the degree of confounding by indication and other biases. No absolute contraindication to antidepressants emerged from this umbrella review.

Surgical Treatment of Degenerative Disk Disease in Three Scandinavian Countries: An International Register Study Based on Three Merged National Spine Registers

STUDY DESIGN

Observational study of prospectively collected data.

OBJECTIVES

Patients with chronic low back pain resistant to nonoperative treatment often face a poor prognosis for recovery. The aim of the current study was to compare the variation and outcome of surgical treatment of degenerative disc disease in the Scandinavian countries based on The International Consortium for Health Outcomes Measurement core spine data sets.

METHODS

Anonymized individual level data from 3 national registers were pooled into 1 database. At the time of surgery, the patient reports data on demographics, lifestyle topics, comorbidity, and data on health-related quality of life such as Oswestry Disability Index, Euro-Qol-5D, and back and leg pain scores. The surgeon records diagnosis, type of surgery performed, and complications. One-year follow-ups are obtained with questionnaires. Baseline and 1-year follow-up data were analyzed to expose any differences between the countries.

RESULTS

A total of 1893 patients were included. At 1-year follow-up, 1315 (72%) patients responded. There were statistically significant baseline differences in age, smoking, comorbidity, frequency of previous surgery and intensity of back and leg pain. Isolated fusion was the primary procedure in all the countries ranging from 84% in Denmark to 76% in Sweden. There was clinically relevant improvement in all outcome measures except leg pain.

CONCLUSIONS

In homogenous populations with similar health care systems the treatment traditions can vary considerably. Despite variations in preoperative variables, patient reported outcomes improve significantly and clinically relevant with surgical treatment.

Combined Aerobic and Resistance Training for Cardiorespiratory Fitness, Muscle Strength, and Walking Capacity after Stroke: A Systematic Review and Meta-Analysis

BACKGROUND

Cardiorespiratory fitness, measured as peak oxygen consumption, is a potent predictor of stroke risk. Muscle weakness is the most prominent impairment after stroke and is directly associated with reduced walking capacity. There is a lack of recommendations for optimal combined aerobic training and resistance training for those patients. The purpose of this study was to systematically review and quantify the effects of exercise training on cardiorespiratory fitness, muscle strength, and walking capacity after stroke.

METHODS

Five electronic databases were searched (until May 2019) for studies that met the following criteria: (1) adult humans with a history of stroke who ambulate independently; (2) structured exercise intervention based on combined aerobic training and resistance training; and (3) measured cardiorespiratory fitness, muscle strength, and/or walking capacity.

RESULTS

Eighteen studies (602 participants, average age 62 years) met the inclusion criteria. Exercise training significantly improved all 3 outcomes. In subgroup analyses for cardiorespiratory fitness, longer training duration was significantly associated with larger effect size. Likewise, for muscle strength, moderate weekly frequency and lower training volume were significantly associated with larger effect size. Furthermore, in walking capacity, moderate weekly frequency and longer training duration were significantly associated with larger effect size.

CONCLUSIONS

These results suggest that an exercise program consisting of moderate-intensity, 3 days per week, for 20 weeks should be considered for greater effect on cardiorespiratory fitness, muscle strength, and walking capacity in stroke patients.

Association of Receiving Multiple, Concurrent Fracture-Associated Drugs With Hip Fracture Risk

IMPORTANCE

Many prescription drugs increase fracture risk, which raises concern for patients receiving 2 or more such drugs concurrently. Logic suggests that risk will increase with each additional drug, but the risk of taking multiple fracture-associated drugs (FADs) is unknown.

OBJECTIVE

To estimate hip fracture risk associated with concurrent exposure to multiple FADs.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study used a 20% random sample of Medicare fee-for-service administrative data for age-eligible Medicare beneficiaries from 2004 to 2014. Sex-stratified Cox regression models estimated hip fracture risk associated with current receipt of 1, 2, or 3 or more of 21 FADs and, separately, risk associated with each FAD and 2-way FAD combination vs no FADs. Models included sociodemographic characteristics, comorbidities, and use of non-FAD medications. Analyses began in November 2018 and were completed April 2019.

EXPOSURE

Receipt of prescription FADs.

MAIN OUTCOMES AND MEASURES

Hip fracture hospitalization.

RESULTS

A total of 11.3 million person-years were observed, reflecting 2 646 255 individuals (mean [SD] age, 77.2 [7.3] years, 1 615 613 [61.1%] women, 2 136 585 [80.7%] white, and 219 579 [8.3%] black). Overall, 2 827 284 person-years (25.1%) involved receipt of 1 FAD; 1 322 296 (11.7%), 2 FADs; and 954 506 (8.5%), 3 or more FADs. In fully adjusted, sex-stratified models, an increase in hip fracture risk among women was associated with the receipt of 1, 2, or 3 or more FADs (1 FAD: hazard ratio [HR], 2.04; 95% CI, 1.99-2.11; P < .001; 2 FADs: HR, 2.86; 95% CI, 2.77-2.95; P < .001; ≥3 FADs: HR, 4.50; 95% CI, 4.36-4.65; P < .001). Relative risks for men were slightly higher (1 FAD: HR, 2.23; 95% CI, 2.11-2.36; P < .001; 2 FADs: HR, 3.40; 95% CI, 3.20-3.61; P < .001; ≥3 FADs: HR, 5.18; 95% CI, 4.87-5.52; P < .001). Among women, 2 individual FADs were associated with HRs greater than 3.00; 80 pairs of FADs exceeded this threshold. Common, risky pairs among women included sedative hypnotics plus opioids (HR, 4.90; 95% CI, 3.98-6.02; P < .001), serotonin reuptake inhibitors plus benzodiazepines (HR, 4.50; 95% CI, 3.76-5.38; P < .001), and proton pump inhibitors plus opioids (HR, 4.00; 95% CI, 3.56-4.49; P < .001). Receipt of 1, 2, or 3 or more non-FADs was associated with a small, significant reduction in fracture risk compared with receipt of no non-FADs among women (1 non-FAD: HR, 0.93; 95% CI, 0.90-0.96; P < .001; 2 non-FADs: HR, 0.84; 95% CI, 0.81-0.87; P < .001; ≥3 non-FADs: HR, 0.74; 95% CI, 0.72-0.77; P < .001).

CONCLUSIONS AND RELEVANCE

Among older adults, FADs are commonly used and commonly combined. In this cohort study, the addition of a second and third FAD was associated with a steep increase in fracture risk. Many risky pairs of FADs included potentially avoidable drugs (eg, sedatives and opioids). If confirmed, these findings suggest that fracture risk could be reduced through tighter adherence to long-established prescribing guidelines and recommendations.

Study methodology in trauma care: towards question-based study designs

The randomized controlled trial (RCT) in surgery may not always be ethical, feasible, or necessary to address a particular research question about the effect of a surgical intervention. If so, properly designed and conducted observational (non-randomized) studies may be valuable alternatives for an RCT and produce credible results. In this paper, we discus differences between RCTs and observational studies and differentiate between three types of comparisons of surgical interventions. We assert that results of different designs should be regarded as complementary to each other when evaluating surgical interventions. Criteria for credible observational research are presented to provide guidance for future observational research of surgical interventions. We argue that the research question that is being asked should guide the discussion about the value of a particular study design.