Retrospective database analysis of 3,219 hospitalized patients in the USA. Very different results in the time period analysis (Table S2), and results significantly different to other studies for the same medications (e.g., heparin OR 3.06 [2.44-3.83]) suggest significant confounding by indication and confounding by time.
Mulhem et al., 4/7/2021, retrospective, database analysis, USA, North America, peer-reviewed, 3 authors.
risk of death, 13.9% higher, RR 1.14, p = 0.21, treatment 300 of 1354 (22.2%), control 216 of 1865 (11.6%), adjusted per study, odds ratio converted to relative risk, Table S1, logistic regression.
This study is excluded in the after exclusion results of meta analysis: substantial unadjusted confounding by indication likely, substantial time varying confounding likely due to declining usage over the early period when overall treatment protocols improved dramatically.
Effect extraction follows pre-specified rules
prioritizing more serious outcomes. For an individual study the most serious
outcome may have a smaller number of events and lower statistical signficance,
however this provides the strongest evidence for the most serious outcomes
when combining the results of many trials.