Depression and frailty are prevalent and burdensome in older age. However, the relationships between these entities are unclear and no quantitative meta- analysis exists. We conducted a systematic review and meta-analysis to investigate the associations between depression and frailty. Two authors searched major electronic databases from inception until November-2016 for cross-sectional/longitudinal studies investigating depression and frailty. The strength of the reciprocal associations between frailty and depression was assessed through odds ratios (ORs) adjusted for potential confounders. From 2306 non duplicated hits, 24 studies were included. The overall prevalence of depression in 8023 people with frailty was 38.60% (95% CI 30.07-47.10, I2=94%). Those with frailty were at increased odds of having depression (OR adjusted for publication bias 4.42, 95%CI 2.66-7.35, k=11), also after adjusting for potential confounders (OR=2.64; 95%CI: 1.59-4.37, I2=55%, k=4). The prevalence of frailty in 2167 people with depression was 40.40% (95%CI 27.00-55.30, I2=97%). People with depression were at increased odds of having frailty (OR=4.07, 95%CI 1.93-8.55, k=8). The pooled OR for incident frailty, adjusted for a median of 7 confounders, was 3.72 (95%CI 1.95-7.08, I2=98%, k=4), whilst in two studies frailty increased the risk of incident depression with an OR=1.90 (95%CI 1.55-2.32, I2=0%). This meta-analysis points to a reciprocal interaction between depression and frailty in older adults. Specifically, each condition is associated with an increased prevalence and incidence of the other, and may be a risk factor for the development of the other. However, further prospective investigations are warranted.

Depression is a prevalent and disabling mental disorder that frequently co-occurs with a wide range of chronic conditions. Evidence has suggested that depression could be associated with excess all-cause mortality across different settings and populations, although the causality of these associations remains unclear. We conducted an umbrella review of systematic reviews and meta-analyses of observational studies. PubMed, PsycINFO, and Embase electronic databases were searched through January 20, 2018. Systematic reviews and meta-analyses that investigated associations of depression and all-cause and cause-specific mortality were selected for the review. The evidence was graded as convincing, highly suggestive, suggestive, or weak based on quantitative criteria that included an assessment of heterogeneity, 95% prediction intervals, small-study effects, and excess significance bias. A total of 26 references providing 2 systematic reviews and data for 17 meta-analytic estimates met inclusion criteria (19 of them on all-cause mortality); data from 246 unique studies (N = 3,825,380) were synthesized. All 17 associations had P < 0.05 per random effects summary effects, but none of them met criteria for convincing evidence. Associations of depression and all-cause mortality in patients after acute myocardial infarction, in individuals with heart failure, in cancer patients as well as in samples from mixed settings met criteria for highly suggestive evidence. However, none of the associations remained supported by highly suggestive evidence in sensitivity analyses that considered studies employing structured diagnostic interviews. In addition, associations of depression and all-cause mortality in cancer and post-acute myocardial infarction samples were supported only by suggestive evidence when studies that tried to adjust for potential confounders were considered. Even though associations between depression and mortality have nominally significant results in all assessed settings and populations, the evidence becomes weaker when focusing on studies that used structured interviews and those that tried to adjust for potential confounders. A causal effect of depression on all-cause and cause-specific mortality remains unproven, and thus interventions targeting depression are not expected to result in lower mortality rates at least based on current evidence from observational studies.

Osteoarthritis (OA) is a leading cause of disability, but the relationship with premature mortality remains uncertain. We aimed to investigate the relationship between OA and mortality from any cause and from cardiovascular disease (CVD). Electronic literature databases searches were conducted to identify prospective studies comparing mortality in a sample of people with and without OA. Risk of all-cause and CVD mortality were summarized using adjusted hazard ratios (HRs) for joint specific (hand, hip, and knee) and joint non-specific OA. New data from the Progetto Veneto Anziani (PRO.V.A.) study were also included. From the PRO.V.A. study (N = 2927), there was no significant increase in mortality risk for participants with any joint OA (N = 1858) compared to non-OA (all-cause, HR = 0.95, 95% CI: 0.77-1.15 and CVD, HR = 1.12, 95% CI: 0.82-1.54). On meta-analysis, seven studies (OA = 10,018/non-OA = 18,541), with a median 12-year follow-up, reported no increased risk of any-cause mortality in those with OA (HR = 1.10, 95% CI: 0.97-1.25). After removing data on hand OA, a significant association between OA and mortality was observed (HR = 1.18, 95% CI: 1.08-1.28). There was a significant higher risk of overall mortality for (1) studies conducted in Europe, (2) patients with multi-joint OA; and (3) a radiological diagnosis of OA. OA was associated with significantly higher CVD mortality (HR = 1.21, 95% CI: 1.10-1.34). People with OA are at increased risk of death due to CVD. The relationship with overall mortality is less clear and may be moderated by the presence of hand OA.