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Background There is debate over whether statins increase risk of hemorrhagic stroke, so we assessed current evidence, including data from new statin trials and trials of nonstatin low‐density lipoprotein‐cholesterol (LDL‐C)– and triglyceride‐lowering therapies. Methods and Results We performed a systematic review of large randomized clinical trials (≥1000 patients with ≥2 years follow‐up) of LDL‐C–lowering therapy (statin, ezetimibe, and PCSK‐9 [proprotein convertase subtilisin/kexin type 9] inhibitor) and triglyceride‐lowering therapy (omega‐3 supplements and fibrate) that reported hemorrhagic stroke as an outcome. We searched MEDLINE, Embase, and Cochrane Library up to July 2, 2021 and updated a meta‐analysis of cardiovascular statin trials published in 2012. Among our several subgroup analyses, we looked at difference depending on stroke status and also depending on age. We identified 37 trials for LDL‐C lowering (284 301 participants) and 11 for triglyceride lowering (120 984 participants). Overall, we found a higher risk of hemorrhagic stroke for LDL‐C lowering, risk ratio (RR) 1.16 (95% CI, 1.01–1.32, P=0.03). For statins (33 trials, 216 258 participants), RR=1.17 (95% CI, 1.01–1.36); for PCSK‐9 inhibitors (2 trials, 46 488 participants), RR=0.86 (95% CI, 0.43–1.74); and for ezetimibe (2 trials, 21 555 participants), RR=1.14 (95% CI, 0.64–2.03). In statin trials of patients with previous stroke/transient ischemic attack, RR was 1.46 (95% CI, 1.05–2.04), and in trials with mean age ≥65 years old, RR=1.34 (95% CI, 1.04–1.73) (Pint=0.14 and Pint=0.23 respectively); for triglyceride lowering (11 trials, 120 984 participants), RR=1.05 (95% CI, 0.86–1.30). Conclusions We found evidence for a small increased risk of hemorrhagic stroke events with LDL‐C–lowering therapies but no clear evidence for triglyceride‐lowering therapies. Registration URL: https://www.crd.york.ac.uk/prospero; Unique identifier: CRD42021275363.

Background Randomized clinical trials (RCTs) might not be representative of the real‐world population because of unreasonable exclusion criteria. We sought to determine which groups of patients are excluded from RCTs that included lipid‐lowering therapy. Methods and Results We retrieved all trials from the Cholesterol Treatment Trialists Collaboration and systematically searched for large (≥1000 participants) lipid‐lowering therapy RCTs, defined as statins, ezetimibe, and PCSK9 inhibitors. We predefined groups: older adults (>70 or >75 years), women, non‐Whites, chronic kidney failure, heart failure, immunosuppression, cancer, dementia, treated thyroid disease, chronic obstructive pulmonary disease, mental illness, atrial fibrillation, multimorbidity (≥2 chronic diseases), and polypharmacy. We counted the number of RCTs excluding patients of the predefined groups and meta‐analyzed the prevalence of included patients to obtain pooled estimates with a random‐effects model. We included 42 RCTs (298 605 patients). Eighty‐one percent of trials excluded patients with severe and 76% those with moderate kidney failure. Seventy‐one percent of trials excluded groups of women, 64% excluded patients with moderate to severe heart failure, 64% those with immunosuppressant conditions, 48% those with cancer, 29% those with dementia, and 29% of trials excluded older adults. The pooled prevalence for patients >70 years of age was 25% (95% CI, 0%–49%), 11% (3%–18%) for >75 years of age, and 51% (38%–63%) for multimorbidity. Conclusions The majority of lipid‐lowering therapy trials excluded patients with common diseases, such as moderate‐to‐severe kidney disease or heart failure or with immunosuppression. Underrepresenting certain populations, including women and older adults, might lead to limited transportability of study results and uncertainty on possible side‐effects and efficacy in these groups. Future trials should promote diversity in the recruitment strategies and improve equity in cardiovascular research. Registration URL: ClinicalTrials.gov; Unique Identifier: CRD42021253909.

Background A cointervention in a randomized clinical trial (RCT) is medical care given in addition to the tested intervention. If cointerventions are unbalanced between trial arms, the results may be biased. We hypothesized that cointerventions would be more adequately reported in RCTs without full blinding or at risk of bias. Methods and Results To describe the reporting of cointerventions and to evaluate the factors associated with their reporting, we did a systematic search of all RCTs evaluating pharmacological interventions on cardiovascular outcomes published in 5 high‐impact journals. The reporting of cointerventions, blinding, and risk of bias were extracted and evaluated independently by 2 reviewers (E.M., L.A.). Cointerventions were inadequately reported in 87 of 123 RCTs (70.7%), with 56 (45.5%) providing no information on cointerventions and 31 (25.2%) providing only partial information. Of the RCTs, 52 (42.3%) had inadequate blinding of participants and/or personnel and 63 (51.2%) of the RCTs were judged at risk of bias. In univariable analysis, the reporting of cointerventions was not associated with blinding of participants and/or personnel (odds ratio [OR], 1.04; 95% CI, 0.47–2.27 for adequately versus inadequately blinded trials) or with risk of bias (OR, 1.47; 95% CI, 0.67–3.21 for at low risk of bias versus trials at risk of bias). In multivariable analysis, only a follow‐up of