Psoriasis risk in patients with type 2 diabetes in German primary care practices.

AIM: To analyze psoriasis risk in type 2 diabetes mellitus (T2DM) patients treated in German primary care practices. METHODS: The study included 87,964 T2DM patients aged 40 years or over who received their initial diabetes diagnosis between 2004 and 2013. Patients were excluded if they had been diagnosed with psoriasis prior to diabetes diagnosis or if the observation period prior to the index date was less than 365 days. After applying these exclusion criteria, 72,148 T2DM patients were included. A total of 72,148 non-diabetic controls were matched (1:1) to T2DM cases based on age, gender, type of health insurance (private or statutory), number of medical visits, and index date. The primary outcome was the diagnosis of psoriasis. Skin infections, dermatitis/eczema, hyperlipidemia, and medications associated with psoriasis (beta blockers, angiotensin-converting enzyme (ACE) inhibitors, lithium, antimalarials, nonsteroidal anti-inflammatory drugs, and benzodiazepines) were included as potential confounders. RESULTS: The mean age was 68.7 years (SD=12.7 years) and 48.6% of subjects were men. Hyperlipidemia, dermatitis/eczema, and skin infections were more frequent in T2DM patients than in controls. Beta blockers, ACE inhibitors, and nonsteroidal anti-inflammatory drugs were also more commonly used in people with T2DM than in controls. A total of 3.4% of T2DM patients and 2.8% of matched controls developed psoriasis within ten years of follow-up (p-value <0.001). T2DM patients were at a higher risk of developing psoriasis than controls (HR=1.18, 95% CI: 1.08-1.29). CONCLUSION: T2DM was positively associated with psoriasis in patients treated in German primary care practices.