Background: Current evidence from randomized controlled trials on statins for primary prevention of cardiovascular disease (CVD) in older people, especially those aged > 75 years, is still lacking. We conducted a systematic review and meta-analysis of observational studies to extend the current evidence about the association of statin use in older people primary prevention group with risk of CVD and mortality. Methods: PubMed, Scopus, and Embase were searched from inception until March 18, 2021. We included observational studies (cohort or nested case-control) that compared statin use vs non-use for primary prevention of CVD in older people aged ≥ 65 years; provided that each of them reported the risk estimate on at least one of the following primary outcomes: all cause-mortality, CVD death, myocardial infarction (MI), and stroke. Risk estimates of each relevant outcome were pooled as a hazard ratio (HR) with a 95% confidence interval (CI) using the random-effects meta-analysis model. The quality of the evidence was rated using the GRADE approach. Results: Ten observational studies (9 cohorts and one case-control study; n = 815,667) fulfilled our criteria. The overall combined estimate suggested that statin therapy was associated with a significantly lower risk of all-cause mortality (HR: 0.86 [95% CI 0.79 to 0.93]), CVD death (HR: 0.80 [95% CI 0.78 to 0.81]), and stroke (HR: 0.85 [95% CI 0.76 to 0.94]) and a non-significant association with risk of MI (HR 0.74 [95% CI 0.53 to 1.02]). The beneficial association of statins with the risk of all-cause mortality remained significant even at higher ages (> 75 years old; HR 0.88 [95% CI 0.81 to 0.96]) and in both men (HR: 0.75 [95% CI: 0.74 to 0.76]) and women (HR 0.85 [95% CI 0.72 to 0.99]). However, this association with the risk of all-cause mortality remained significant only in those with diabetes mellitus (DM) (HR 0.82 [95% CI 0.68 to 0.98]) but not in those without DM. The level of evidence of all the primary outcomes was rated as “very low.” Conclusions: Statin therapy in older people (aged ≥ 65 years) without CVD was associated with a 14%, 20%, and 15% lower risk of all-cause mortality, CVD death, and stroke, respectively. The beneficial association with the risk of all-cause mortality remained significant even at higher ages (> 75 years old), in both men and women, and in individuals with DM, but not in those without DM. These observational findings support the need for trials to test the benefits of statins in those above 75 years of age.

A systematic review and meta-analysis of published randomized controlled trials was performed to update the present evidence about the safety and efficacy of dexamethasone combined with other antiemetics versus single antiemetics for the prevention of postoperative nausea and vomiting after laparoscopic cholecystectomy. A computer literature search of PubMed, Scopus, Web of Science and Embase was conducted to identify the relevant randomized controlled trials. In addition, a manual search of reference lists of the retrieved articles was conducted. Relevant outcomes were pooled as odds ratio (OR) by RevMan version 5.3 for windows. Pooled data from 14 RCTs (1542 patients) favored dexamethasone combined with other antiemetics over single antiemetics as a prophylaxis against postoperative nausea and vomiting after laparoscopic cholecystectomy in the early postoperative period (OR = 0.39, 95% CI [0.27 to 0.54], p < 0.00001), late postoperative period (OR = 0.36, 95% CI [0.23 to 0.56], p < 0.00001), and overall postoperative period (OR = 0.34, 95% CI [0.23 to 0.51], p < 0.00001). Subsequently, rescue antiemetic usage was significantly lower in the combination group (OR = 0.25, 95% CI [0.16 to 0.41], p < 0.00001). Subgroup analysis showed that all combinations of dexamethasone and other antiemetics were superior to corresponding singel antiemetics except for the combination of dexamethasone and ramosetron which was not superior to ramosetron alone in all postoperative periods and the combination of dexamethasone and granisetron which was not superior to granisetron alone in the early postoperative period (OR = 0.26, 95% CI [0.07 to 1.01], p = 0.05). For all adverse events, there was no significant difference between the two groups. Dexamethasone combined with other antiemetics provided better prophylaxis than single antiemetics against postoperative nausea and vomiting after laparoscopic cholecystectomy. The underlying mechanism of dexamethasone action and its optimal dose should be further investigated.