DERBY, Connecticut—Among people who have osteoporosis, 20% are men. Approximately 12% of elderly men take the loop diuretic furosemide, and data from the Osteoporotic Fractures in Men Study have now linked this type of diuretic to increased loss of bone mineral density (BMD) in older men. Lionel S. Lim, MD, MPH, reported on behalf of the study group in Archives of Internal Medicine.¹

”Our study suggests that older community-dwelling men taking loop diuretics have increased rates of hip bone loss. Compared with rates of hip bone loss among nonusers of diuretics, adjusted rates of loss were about 2-fold greater among intermittent loop diuretic users and about 2.5-fold greater among continuous loop diuretic users,” wrote Dr. Lim from Griffin Hospital, in Derby, Connecticut.

Consider bone loss risk before prescribing loop diuretics

Loop diuretics are prescribed for congestive heart failure and to treat hypertension, especially hypertension associated with renal impairment. Furosemide was the sixth most commonly prescribed generic drug in the US in 2005 and was the most commonly prescribed drug among community-dwelling older men.

Because loop diuretics inhibit the sodium-potassium-chloride cotransporter in the loop of Henle, these agents increase urinary calcium excretion, which can lead to bone loss. The drugs have been associated with increased risk of hip fracture in observational studies, but the underlying mechanism was uncertain.  

The researchers suspected that loop diuretic use in older men might be associated with increased rates of bone loss at the hip. To test this possibility, they analyzed medication use and measured hip BMD at baseline and again about 5 years later.

The cohort study enrolled 3269 men aged ≥65 years, including 84 men who were continuous users of loop diuretics, 181 intermittent users, and 3004 nonusers. The analysis included adjustments for age, baseline BMD, body mass index, weight change, physical activity, smoking, diabetes mellitus, chronic obstructive pulmonary disease, congestive heart failure, hypertension, and statin use.

Dr. Lim reported that average annual rate of decline in total hip BMD was:

• -0.33% in nonusers of loop diuretics
• -0.58% in intermittent users of loop diuretics
• -0.78% in continuous users of loop diuretics.

Similar bone weakening occurred at the femoral neck and at the trochanter.

“Men who were continuous loop diuretics users had the greatest average rate of bone loss at the total hip compared with intermittent users and nonusers of loop diuretics. Their rate of bone loss was almost 3-fold greater than that of nonusers and 1.5-fold greater than that of intermittent users after adjustment for age and baseline BMD,” Dr. Lim said. “We conclude that loop diuretic use in older men is associated with increased rates of hip bone loss. These results suggest that the potential for bone loss should be considered when loop diuretics are prescribed to older patients in clinical practice.”

Reference

1. Lim LS, Fink HA, Kuskowski MA, et al. Loop diuretic use and increased rates of hip bone loss in older men. The Osteoporotic Fractures in Men Study. Arch Intern Med. 2008;168:735-740.