Detecting Selection Bias in Observational Studies—When Interventions Work Too Fast

Mohyuddin, Ghulam Rehman; Prasad, Vinay

doi:10.1001/jamainternmed.2023.2067

Cited by 7 publications

(5 citation statements)

References 9 publications

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“…Within 1 year, those who had received sub‐therapeutic ECT had a very similar OR for all‐cause mortality as those who had received therapeutic ECT. Further, when inspecting the Kaplan‐Meier curves we could see a separation in mortality happening implausibly early, which might indicate selection bias 45 . Potential mechanisms by which ECT may increase survival are both behavioral and biological.…”

Section: Discussionmentioning

confidence: 97%

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Suicidal behavior and all‐cause mortality in depressed older adults aged 75+ treated with electroconvulsive therapy: A Swedish register‐based comparison study

Hedna,

Jonson,

Sigström

et al. 2024

Int J Geriat Psychiatry

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ObjectivesElectroconvulsive therapy (ECT) is effective in treating late‐life depression. There is limited research on suicidal behavior and all‐cause mortality in the oldest old after ECT.MethodsOlder adults aged 75 years and above who had been inpatients for moderate to severe depression between January 1, 2011, and December 31, 2017, were included in the study. We used exact and propensity score matching to balance groups. We compared suicidal behavior (fatal and non‐fatal) and all‐cause mortality in those who had received ECT and those with other depression treatments.ResultsOf the study population, 1802 persons who received ECT were matched to 4457 persons with other treatments. There were no significant differences in the risk of suicidal behavior between groups, (within 3 months: odds ratio 0.73; 95% confidence intervals (CI), 0.44–1.23, within 4 months to 1 year: aOR 1.34; 95% CI, 0.84–2.13). All‐cause mortality was lower among ECT recipients compared to those who had received other treatments, both within 3 months (aOR, 0.35; 95% CI, 0.23–0.52), and within 4 months to 1 year (aOR 0.65; 95% CI, 0.50–0.83).ConclusionsCompared to other depression treatments, ECT is not associated with a higher risk of suicidal behavior in patients aged 75 and above. ECT is associated with lower all‐cause mortality in this age group, but we advise caution regarding causal inferences.

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Section: Discussionmentioning

confidence: 97%

“…Further, when inspecting the Kaplan-Meier curves we could see a separation in mortality happening implausibly early, which might indicate selection bias. 45 Potential mechanisms by which ECT may increase survival are both behavioral and biological.…”

Section: Discussionmentioning

confidence: 99%

Suicidal behavior and all‐cause mortality in depressed older adults aged 75+ treated with electroconvulsive therapy: A Swedish register‐based comparison study

Hedna,

Jonson,

Sigström

et al. 2024

Int J Geriat Psychiatry

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“…Post hoc adjustments may be wholly inadequate for controlling for underlying bias [ 11 ]. Specific natural experiment study designs, such as regression discontinuity, may allow for causal inference if falsification data are included [ 25 ]. Adequately powered randomized studies remain an even more reliable way to determine VE against severe disease.…”

Section: Discussionmentioning

confidence: 99%

“…Alternatively, one can identify evidence of healthy vaccinee bias if a decrease in death rate among the vaccinated occurs too quickly to be attributable to the vaccine [ 25 ]. This bias can be demonstrated visually in a Kaplan–Meier curve, which reveals a difference in death rates by vaccination status within days of the first dose of vaccination (before an effect against death is expected).…”

Section: Introductionmentioning

confidence: 99%

The importance of falsification endpoints in observational studies of vaccination to prevent severe disease: A critique of a harm–benefit analysis of BNT162b2 vaccination of 5- to 11-year-olds

Høeg,

Haslam,

Prasad

2024

Epidemiol. Infect.

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We explore one systematic review and meta-analysis of both observational and randomized studies examining COVID-19 vaccines in 5-to 11-year-olds, which reported substantial benefits associated with vaccinating this age group. We discuss the limitations of the individual studies that were used to estimate vaccination benefits. The review included five observational studies that evaluated vaccine effectiveness (VE) against COVID-19 severe disease or hospitalization. All five studies failed to adequately assess differences in underlying health between vaccination groups. In terms of vaccination harms, looking only at the randomized studies, a significantly higher odds of adverse events was identified among the vaccinated compared with the unvaccinated. Observational studies are at risk of overestimating the effectiveness of vaccines against severe disease if healthy vaccinee bias is present. Falsification endpoints can provide valuable information about underlying healthy vaccinee bias. Studies that have not adequately ruled out bias due to better health among the vaccinated or more vaccinated should be viewed as unreliable for estimating the VE of COVID-19 vaccination against severe disease and mortality. Existing systematic reviews that include observational studies of the COVID-19 vaccine in children may have overstated or falsely inferred vaccine benefits due to unidentified or undisclosed healthy vaccinee bias. Epidemiology and Infection www.cambridge.org/hygOpinions -For debate Cite this article: Høeg TB, Haslam A and Prasad V (2024). The importance of falsification endpoints in observational studies of vaccination to prevent severe disease: A critique of a harm-benefit analysis of BNT162b2 vaccination of 5-to 11-year-olds.

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“…5,6,41 Rates of TKA are increasing markedly, vary considerably by region, and may be influenced by several factors related to the patients, clinicians, and health systems. 2,[42][43][44][45][46][47][48][49][50] Controlling for these factors in studies is challenging, especially in observational designs, 51,52 and may result in overestimating a causal effect of knee arthroscopic surgery on delaying or hastening TKA.…”

Section: Introductionmentioning

confidence: 99%

Incidence of Total Knee Arthroplasty After Arthroscopic Surgery for Knee Osteoarthritis

Birmingham,

Primeau,

Shariff

et al. 2024

JAMA Netw Open

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ImportanceIt is unclear whether arthroscopic resection of degenerative knee tissues among patients with osteoarthritis (OA) of the knee delays or hastens total knee arthroplasty (TKA); opposite findings have been reported.ObjectiveTo compare the long-term incidence of TKA in patients with OA of the knee after nonoperative management with or without additional arthroscopic surgery.Design, Setting, and ParticipantsIn this ad hoc secondary analysis of a single-center, assessor-blinded randomized clinical trial performed from January 1, 1999, to August 31, 2007, 178 patients were followed up through March 31, 2019. Participants included adults diagnosed with OA of the knee referred for potential arthroscopic surgery in a tertiary care center specializing in orthopedics in London, Ontario, Canada. All participants from the original randomized clinical trial were included. Data were analyzed from June 1, 2021, to October 20, 2022.ExposuresArthroscopic surgery (resection or debridement of degenerative tears of the menisci, fragments of articular cartilage, or chondral flaps and osteophytes that prevented full extension) plus nonoperative management (physical therapy plus medications as required) compared with nonoperative management only (control).Main Outcomes and MeasuresTotal knee arthroplasty was identified by linking the randomized trial data with prospectively collected Canadian health administrative datasets where participants were followed up for a maximum of 20 years. Multivariable Cox proportional hazards regression models were used to compare the incidence of TKA between intervention groups.ResultsA total of 178 of 277 eligible patients (64.3%; 112 [62.9%] female; mean [SD] age, 59.0 [10.0] years) were included. The mean (SD) body mass index was 31.0 (6.5). With a median follow-up of 13.8 (IQR, 8.4-16.8) years, 31 of 92 patients (33.7%) in the arthroscopic surgery group vs 36 of 86 (41.9%) in the control group underwent TKA (adjusted hazard ratio [HR], 0.85 [95% CI, 0.52-1.40]). Results were similar when accounting for crossovers to arthroscopic surgery (13 of 86 [15.1%]) during follow-up (HR, 0.88 [95% CI, 0.53-1.44]). Within 5 years, the cumulative incidence was 10.2% vs 9.3% in the arthroscopic surgery group and control group, respectively (time-stratified HR for 0-5 years, 1.06 [95% CI, 0.41-2.75]); within 10 years, the cumulative incidence was 23.3% vs 21.4%, respectively (time-stratified HR for 5-10 years, 1.06 [95% CI, 0.45-2.51]). Sensitivity analyses yielded consistent results.Conclusions and RelevanceIn this secondary analysis of a randomized clinical trial of arthroscopic surgery for patients with OA of the knee, a statistically significant association with delaying or hastening TKA was not identified. Approximately 80% of patients did not undergo TKA within 10 years of nonoperative management with or without additional knee arthroscopic surgery.Trial RegistrationClinicalTrials.gov Identifier: NCT00158431

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Detecting Selection Bias in Observational Studies—When Interventions Work Too Fast

Abstract: This Viewpoint discusses the limitations that observational studies have in drawing causal inferences.

Cited by 7 publications

References 9 publications

Suicidal behavior and all‐cause mortality in depressed older adults aged 75+ treated with electroconvulsive therapy: A Swedish register‐based comparison study

Suicidal behavior and all‐cause mortality in depressed older adults aged 75+ treated with electroconvulsive therapy: A Swedish register‐based comparison study

The importance of falsification endpoints in observational studies of vaccination to prevent severe disease: A critique of a harm–benefit analysis of BNT162b2 vaccination of 5- to 11-year-olds

Incidence of Total Knee Arthroplasty After Arthroscopic Surgery for Knee Osteoarthritis

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