Smoking, hypertension up severe diabetic retinopathy risk in diabetics

Though rare, severe nonproliferative and proliferative diabetic retinopathy (NPDR/PDR) remain public health threats, and holistic strategies are needed to control diabetes and other lifestyle risk factors, such as smoking and blood pressure, a new Iran study has found.

The study included 1,169 participants (aged ≥20 years, 675 women) with type 2 diabetes mellitus (T2DM). The history of pan-retinal photocoagulation related to DR was collected by a trained interviewer.

Over a median follow-up of 12.7 years, 187 cases of severe NPDR/PDR were detected, yielding an incidence rate of 13.6 per 1,000 person-years. Annually, this corresponded to 1.36 percent of T2DM patients developing severe NPDR/PDR. Incidence was higher in women than in men (15.5 vs 10.8 per 1,000 person-years).

Multivariable Cox proportional hazard regression analysis found that being overweight (hazard ratio [HR], 0.60, 95 percent confidence interval [CI], 0.39–0.92; p=0.02) and obese (HR, 0.48, 95 percent CI, 0.27–0.83; p=0.01) were significant protective factors against severe NPDR/PDR.

On the other hand, current smoking increased the risk of severe NPDR/PDR by 75 percent (HR, 1.75, 95 percent CI, 1.12–2.74; p=0.02), as did pre-hypertension (HR, 1.65, 95 percent CI, 1.05–2.58; p=0.03) and newly diagnosed hypertension (HR, 1.96, 95 percent CI, 1.06–3.65; p=0.03).

“To the best of our knowledge, this is the first long-term study that has reported the various risk factors related to the progression of severe-NPDR/PDR in the Middle East and North Africa region with a high burden of diabetes. Moreover, our findings stem from a population-based study rather than data derived from hospitalized surveys which may confound the results,” the researchers said.