Objectives: Cancer patients with comorbid diabetes have a 50% increased risk of all-cause mortality compared with cancer patients without diabetes. Less attention to diabetes management (glucose control, medication adherence, and diabetes self-management behaviors) during active cancer treatment is hypothesized as an explanation for worse outcomes among diabetic cancer patients. The objective of this systematic review is to determine and quantify how a cancer diagnosis impacts diabetes management.
Methods: Quantitative and qualitative studies evaluating diabetes management among patients were identified by searching 4 databases: MEDLINE, EMBASE, The Cochrane Library, and Web of Science. Two independent reviewers extracted data and summarized results from eligible studies. Study quality was formally assessed.
Results: Thirty-six studies met all inclusion criteria. We observed heterogeneity across studies in terms of study design, sample size, cancer site, type of diabetes management evaluated, and quality. Numerous articles discussed that overall, glucose control, medication adherence, and diabetes self-management behaviors declined following a cancer diagnosis. However, findings were inconsistent across studies.
Conclusions: Although the effects of a cancer diagnosis on diabetes management are mixed, when results across studies were synthesized together, diabetes management appeared to generally decline after a cancer diagnosis. Declines in diabetes management seem to be primarily due to shifts in the priority of care from diabetes management to cancer. A next critical step in this line of work is to identify patient and provider level predictors of better or worse diabetes management to design and test interventions aimed at improving effective diabetes management for cancer patients.