Type 2 diabetes mellitus risk associated with sarcoidosis: A Swedish population-based cohort study

The rate of type 2 diabetes mellitus (T2D) is increased in patients with sarcoidosis but it is unknown how corticosteroid (CS) treatment plays a role. We investigated whether T2D risk is higher in sarcoidosis patients compared to the general population and if it varies by time since sarcoidosis diagnosis and CS treatment. Individuals with ≥2 ICD codes for sarcoidosis were identified from the National Patient Register (NPR; n=8165). CS dispensations ±3 mo from 1st sarcoidosis diagnosis were identified from the Prescribed Drug Register (PDR). A general population comparator without sarcoidosis was matched to cases 10:1 on age, sex and region of residence (n=85151). Incident T2D was obtained using ICD codes (NPR) and anti-diabetic drug dispensations (PDR). Follow-up was from 2nd sarcoidosis diagnosis/matching date until T2D, emigration, death or study end (Dec 2013). Cox regression models adjusted for age, sex and education estimated hazard ratios (HR 95%CI). We examined the variation in T2D risk over time using flexible parametric survival models. The sarcoidosis cases were 54% male, mean age was 51 yrs and 36% were CS-treated at diagnosis. The T2D rate was 9.7/1000 person-yrs in untreated sarcoidosis, 15.5 in CS-treated sarcoidosis and 6.6 in comparators. The HR for T2D was 1.5 (95%CI 1.3-1.8) associated with untreated sarcoidosis and 2.6 (95%CI 2.2-3.0) associated with CS-treated sarcoidosis. Flexible parametric models showed the T2D risk was highest for CS-treated sarcoidosis in the 2 yrs after diagnosis. Sarcoidosis is associated with an increased risk of T2D especially in CS-treated patients at diagnosis. This group of patients therefore needs to be more closely monitored for T2D.