The newer prostate-specific alpha blockers produce a small but significant increase in the risk of falls in older men with lower urinary tract symptoms (LUTS), a study from Canada has shown.

The investigators looked at the incidence of falls and fractures in men commencing tamsulosin, alfuzosin or silodosin for LUTS, using community datasets, in a matched cohort study.

The alpha blocker cohort consisted of 147,084 men aged 66 years and over, starting a selective alpha blocker (84% tamsulosin). An equal cohort of matched men, not taking alpha blockers was created on a 1:1 basis.

The primary outcome measures were falls and fractures 90 days after initiation of therapy. Secondary outcomes were major osteoporotic fractures, hip fractures, hypotension and head trauma.

Risk of falling was higher in men taking alpha blockers compared with the unexposed cohort:

• Odds ratio (OR) 1.14 (95% CI: 1.07-1.21)

• Absolute increased risk 0.17%

Likewise, risk of fractures was increased:

• OR 1.16 (95% CI: 1.04-1.29)

• Absolute increased risk 0.06%

The two outcomes appeared to be inter-related as 80% of those who sustained a fracture also had a fall.

Secondary outcomes were also significantly increased in the alpha blocker group:

• Hypotension OR 1.80 (95% CI: 1.59-2.03)

• Head trauma OR 1.15 (95% CI: 1.04-1.27)

The authors conclude that alpha blockers are associated with a small but significant increase in the risk of falls and an increase in the risk of fractures of 16% in the first 90 days of use.

This could seem alarming, but it is important to remember that this is a large study, powered to detect statistically significant differences at a small effect size. The absolute increased risk of falls and fractures is small, and the number needed to harm in the 90 days after initiation of a selective alpha blocker is 588 for falls, and 1,666 for fracture.

Thus, it is important to counsel men that if they experience postural symptoms on an alpha blocker they should have a discussion with the prescribing doctor about reviewing the risk:benefit ratio.

However, we should not overplay the risk of prescribing these medications which for many men with LUTS can transform their quality of life.

Dr Jonathan Rees