Serum potassium is an age-dependent risk factor for pre-diabetes and diabetes in the Israeli population

Objective: We analysed the association between serum potassium, within the normal range, and early signs of diabetes in an Israeli population. Research design and methods: A computerized database of the Clalit Health Services was used for obtaining information regarding patients' baseline serum potassium levels. The main study outcome was dysglycaemia, defined as fasting glucose > 100 mg/dL, HbA1C > 6.5 gr% (48 mmol/mol) or a new diagnosis of diabetes. A secondary outcome was overt diabetes. Results: Included in the study were 71,597 patients, mean age 40.8 +/- 13.4 years. After a mean follow-up period of 5.3 +/- 2.2 years, dysglycaemia decreased [odds ratio (OR) = 0.95; 95% confidence interval (CI) = 0.906-0.997; p = 0.038], as did the incidence of overt diabetes (OR = 0.86; 95% CI = 0.793-0.934; p = 0.0001), for every 1 mmol/L elevation in serum potassium in the normal range. But analysis of subpopulation reveals that when elevated serum potassium was associated with low adjusted ORs for predicting dysglycaemia (OR = 0.904 with a 95% CI of 0.849-0.963; p = 0.002), the opposite effect was demonstrated over the age of 41 years (OR = 1.113 with a 95% CI of 1.048-1.104; p < 0.001). Conclusions: This study demonstrates age-related association between serum potassium and the risk of dysglycaemia.