Heat as a prognostic factor for the development and progression of diabetes: a systematic review and meta-analysis

OBJECTIVES: This is a protocol for a Cochrane Review (prognosis). The objectives are as follows: To assess the prognostic value of ambient heat exposures as a risk factor for diabetes and diabetes progression. This objective can be framed in two syntheses following the PICOTS scheme as demonstrated in Table 1. Table 1. PICOTS for the review questions Synthesis 1: Heat as a prognostic factor for the development of diabetes Synthesis 2: Heat as a prognostic factor for outcomes in people living with diabetes Population Persons of any age without diabetes Persons of any age with type 1 diabetes, type 2 diabetes, gestational diabetes mellitus, or other types of diabetes Index prognostic factor Different ambient heat exposures, including heatwaves, increasing temperatures, and seasonal variations of temperatures Comparator Persons exposed to non-extreme lower temperatures Outcomes Incidence of diabetes Diabetes progression Including all-cause mortality, hospital admissions, CVD incidence, nephropathy incidence, retinopathy incidence, neuropathy incidence, health-related quality of life, glycaemic control, blood lipids, blood pressure, renal and inflammatory biomarkers, acute complications, progression of neuropathy, and mental and cognitive disorders Timing Ambient heat exposures, including heatwaves, increasing temperatures, and seasonal variations of temperatures as defined by the original studies, ranging from a few hours to several years depending on the prognostic factor and study design Setting No restrictions on setting, including data from both high-income countries and low- and middle-income countries.