Economic aspects of the association between diabetes and depression: a systematic review

Background: The importance of co-morbid diabetes and depression is gaining increased attention. Quantifying the socio-economic and clinical impacts of co-morbidity is important given the high costs of these diseases. This review synthesised evidence on the economic impact of co-morbidity and potential cost-effectiveness of prevention and treatment strategies.

Methods: 11 databases from 1980 until June 2011 searched. In addition, websites and reference lists of studies scrutinised and hand search of selected journals performed. Reviewers independently assessed abstracts, with economic data extracted from relevant studies.

Results: 62 studies were identified. 47 examined the impact of co-morbidity on health care and other resource utilisation. 11 of these included productivity losses, although none quantified the impact of mortality. Most demonstrated an association between co-morbidity and increasing health service utilisation and cost. Adverse impacts on workforce participation and absenteeism were found. 15 economic evaluations were also identified. Most focused on primary care led collaborative and/or stepped care, suggesting actions may be cost effective. We did not identify any studies looking at actions to reduce the risk of diabetes in people with depression.

Limitations: Most studies are set in the US, which may be due to focus on English language databases. Few studies looked at impacts beyond one year or outside the health care system.

Conclusions: There is an evidence base demonstrating the adverse economic impacts of co-morbid diabetes and depression and potential for cost effective intervention. This evidence base might be strengthened through modelling studies on cost effectiveness using different time periods, contexts and settings.