Uses of real-world data in drug safety and effectiveness studies are often challenged by various sources of bias. We undertook a systematic search of the published literature through September 2020 to evaluate the state of use and utility of negative controls to address bias in pharmacoepidemiologic studies. Two reviewers independently evaluated study eligibility and abstracted data. Our search identified 184 eligible studies for inclusion. Cohort studies (115, 63%) and administrative data (114, 62%) were, respectively, the most common study design and data type used. Most studies used negative control outcomes (91, 50%), and for most studies the target source of bias was unmeasured confounding (93, 51%). We identified 4 utility domains of negative controls: 1) bias detection (149, 81%), 2) bias correction (16, 9%), 3) P-value calibration (8, 4%), and 4) performance assessment of different methods used in drug safety studies (31, 17%). The most popular methodologies used were the 95% confidence interval and P-value calibration. In addition, we identified 2 reference sets with structured steps to check the causality assumption of the negative control. While negative controls are powerful tools in bias detection, we found many studies lacked checking the underlying assumptions. This article is part of a Special Collection on Pharmacoepidemiology.

Despite a growing prevalence of respiratory diseases in recent decades in China, limited evidence is available on the health and economic burden of chronic obstructive pulmonary disease (COPD). We estimated the 20-year health and economic burden of COPD in China from 2020 to 2039. We created a probabilistic dynamic open-cohort Markov model of COPD for the Chinese population aged ≥40 years. Projections of population growth and urbanization rates were obtained from the United Nations Population Division. Other parameter inputs including smoking prevalence, COPD prevalence and severity distributions, disease-related costs, and utility weights were obtained from the most recent published literature. We modeled number of COPD patients, excess mortality due to COPD, exacerbations, COPD-attributable losses of quality-adjusted life-years, and direct and indirect COPD costs over the 20 years. The number of COPD patients was projected to increase from 88.3 million in 2020 to 103.3 million in 2039. The projected total losses of quality-adjusted life-years and the excess mortality due to COPD were, respectively, estimated to be 253.6 million and 3.9 million over the 20 years. The projected 20-year total discounted direct and indirect costs of COPD were, respectively, $3.1 trillion and $360.5 billion. The projected health and economic burden was higher in males and urban areas. COPD is projected to inflict a substantial burden to the society and the health care system in China. Effective strategies for prevention and early management of COPD are needed to mitigate the forthcoming disease burden.

Background: While forced expiratory volume in 1 s (FEV₁) is a hallmark of disease progression in chronic obstructive lung diseases, little is known about the relationship between baseline FEV₁and future risks of other medical conditions.Objective: The aim of this study was to investigate the association between baseline FEV₁and future risks of diabetes, asthma, myocardial infarction, hypertension and all-cause mortality.Methods: We used data from the National Health and Nutrition Examination Survey and its Epidemiological Follow-Up Study. Our data provided longitudinal follow-up of the original cohort for up to 12 years. We used two competing risks approaches, the cause-specific hazard model and the Fine–Gray sub-distribution hazard model, to measure the associations between baseline FEV₁and future risks of the outcomes of interest. All models were adjusted for major confounding factors.Results: The final sample included 3020 participants (mean±sdbaseline age 44.64±13.44 years). In the cause-specific hazard model, for every per cent increase in the baseline per cent predicted FEV₁, the hazard of the event reduced by 2.5% (HR 0.975; 95% CI 0.958–0.994) for diabetes, 4.3% (HR 0.957; 95% CI 0.932–0.983) for asthma and 1.8% (HR 0.982; 95% CI 0.971–0.992) for all-cause mortality. There was no statistically significant association between baseline per cent predicted FEV₁and future risks of myocardial infarction (HR 0.987; 95% CI 0.970–1.004) and hypertension (HR 0.998; 95% CI 0.992–1.005). Consistent results were observed for the Fine–Gray sub-distribution hazard model.Conclusion: Our data suggest that lower per cent predicted FEV₁values at baseline were significantly associated with higher future risks of diabetes, asthma and all-cause mortality.

Undertreatment of depression is common among children and adolescents, but evidence of the impact of undertreatment of depression on risk of suicide is limited due to the low base rate of suicide in the population and lack of sufficient data sources. We developed a microsimulation model that uses evidence from multiple sources to study the impact of different durations of antidepressant treatment on suicide risk in a synthesized sample that is nationally representative of children and adolescents with major depressive disorder. Compared with receiving no treatment, suicide rate and risk of suicide attempt both decreased with increasing duration of antidepressant treatment (for 12 weeks, suicide rate ratios = 0.78 (95% credible interval (CrI): 0.58, 1.15), 36 weeks, 0.65 (95% CrI: 0.44, 0.90), and 52 weeks, 0.63 (95% CrI: 0.45, 0.72); for suicide attempt: 12 weeks, suicide risk ratios = 0.68 (95% CrI: 0.62, 0.69), 36 weeks, 0.56 (95% CrI: 0.52, 0.57), and 52 weeks, 0.55 (95% CrI: 0.51, 0.56). The suicide rate and risk of suicide attempt were lower in children than in adolescents. Males had a lower risk of suicide attempt but higher suicide rate than females. The findings from the microsimulation model show that completion of 12–36 weeks of antidepressant treatment may reduce suicide attempt and suicide among children and adolescents with major depressive disorder.

Background: Most universities that re-open in the United States (US) for in-person instruction have implemented the Centers for Disease Prevention and Control (CDC) guidelines. The value of additional interventions to prevent the transmission of SARS-CoV-2 is unclear. We calculated the cost-effectiveness and cases averted of each intervention in combination with implementing the CDC guidelines.Methods: We built a decision-analytic model to examine the cost-effectiveness of interventions to re-open universities. The interventions included implementing the CDC guidelines alone and in combination with 1) a symptom-checking mobile application, 2) university-provided standardized, high filtration masks, 3) thermal cameras for temperature screening, 4) one-time entry (‘gateway’) polymerase chain reaction (PCR) testing, and 5) weekly PCR testing. We also modeled a package of interventions (‘package intervention’) that combines the CDC guidelines with using the symptom-checking mobile application, standardized masks, gateway PCR testing, and weekly PCR testing. The direct and indirect costs were calculated in 2020 US dollars. We also provided an online interface that allows the user to change model parameters.Results: All interventions averted cases of COVID-19. When the prevalence of actively infectious cases reached 0.1%, providing standardized, high filtration masks saved money and improved health relative to implementing the CDC guidelines alone and in combination with using the symptom-checking mobile application, thermal cameras, and gateway testing. Compared with standardized masks, weekly PCR testing cost $9.27 million (95% Credible Interval [CrI]: cost-saving-$77.36 million)/QALY gained. Compared with weekly PCR testing, the ‘package’ intervention cost $137,877 (95% CrI: $3,108-$19.11 million)/QALY gained. At both a prevalence of 1% and 2%, the ‘package’ intervention saved money and improved health compared to all the other interventions.Conclusions: All interventions were effective at averting infection from COVID-19. However, when the prevalence of actively infectious cases in the community was low, only standardized, high filtration masks clearly provided value.