People living with HIV face an increased risk of deep vein thrombosis (DVT)—potentially dangerous blood clots in major blood vessels—according to a Johns Hopkins University School of Medicine study published in the July 1 issue of the Journal of Acquired Immune Deficiency Syndromes.

Left undiagnosed and untreated, DVT can cause pain, swelling and numbness-usually in the legs-and can also travel to the pulmonary artery in the chest and cause a life-threatening blockage (pulmonary embolism). Studies suggest that 1 to 2 percent of HIV-positive people develop DVT at some point in their lives, which is a rate 10 times higher than expected among people without HIV.

To confirm these results, Aima Ahonkhai, MD, and her colleagues investigated the incidence of DVT among patients in the Johns Hopkins University AIDS Service cohort. They found the risk of DVT among HIV-positive patients to be approximately 0.54 percent per patient per year—comparable to what has been reported by other research teams. Compared with patients in the cohort who hadn’t developed DVT, those who did were more likely to have slightly lower CD4 counts, higher viral loads and low hemoglobin levels preceding their DVT diagnosis. The use of antiretroviral therapy was not associated with DVT.

The authors suggest further studies elucidating why DVT risk is higher in people living with HIV are important. They write, “…the mortality from [pulmonary embolism] is high, and the morbidity from DVT is great. With the tremendous recent gains in life expectancy for patients with HIV/AIDS, addressing the threat of [DVT] is increasingly appropriate.”