Frailty, not comorbidity, predicted trouble after continence surgery

Design

Retrospective cohort of Medicare beneficiaries 2014 to 2016, generalised linear regression with robust standard errors

Population

7,252 men undergoing artificial urinary sphincter (62.2%) or male sling (37.8%), mean age 74.2 years

Primary outcome

Thirty-day complications, and device revision or removal within one year

Effect

Thirty-day complications adjusted RR 1.5 prefrail and 2.5 frail vs not frail (global p = 0.0001); revision or removal aRR 1.2 and 1.3 (p = 0.04)

Seven thousand two hundred and fifty-two Medicare beneficiaries who had an artificial urinary sphincter (62.2%) or a male sling (37.8%) between 2014 and 2016 were analysed, with baseline frailty measured by a claims-based frailty index and grouped as not frail, prefrail or mildly-to-severely frail. Mean age was 74.2 years. Thirty-day complications occurred in 15% and device revision or removal within a year in 11%.

Complications rose with frailty independently of age and comorbidity: adjusted relative risk 1.5 for prefrail and 2.5 for mildly-to-severely frail against not frail. Age and Charlson comorbidity index each contributed separately. For device revision or removal the pattern held for frailty (adjusted relative risk 1.2 and 1.3) and for age, but not for the Charlson index at all — comorbidity burden simply did not predict whether the device would need revising, while frailty did.

That dissociation is the useful part. Preoperative assessment for these operations is usually built around comorbidity scores and anaesthetic risk, which this study suggests are the wrong instrument for the question a man actually asks: will the device still be working in a year. Frailty is measurable in clinic in a few minutes — gait speed, grip, unintentional weight loss, exhaustion, activity level — and does not need a claims database. Measure it, record it, and use it in the conversation about whether a sphincter or a sling is the right operation, and about the realistic chance of a second procedure. The data are retrospective and from a US insurance population, so the absolute rates will not transfer, but the direction is unlikely to be an artefact of coding.

• Assess frailty formally before offering an artificial urinary sphincter or male sling.
• Use a bedside frailty measure — gait speed, grip, weight loss, exhaustion, activity — not the comorbidity score alone.
• Quote the risk of revision or removal, about 11% at one year overall, when consenting.
• Note that comorbidity burden did not predict revision or removal; frailty did.
• Absolute rates come from a US Medicare population and will not transfer directly.

The statistics, in plain English

An adjusted relative risk of 2.5 means the frailest men had about two and a half times the 30-day complication rate of the non-frail after accounting for age and comorbidity — a large effect for a preoperative variable that is rarely recorded. The more informative result is negative: the Charlson comorbidity index predicted complications but not device revision, with a global p of 0.2. Two exposures that behave differently across two outcomes are unlikely to be measuring the same underlying thing, which is the argument that frailty is adding information rather than restating comorbidity. The design remains retrospective and claims-based, so the frailty index is derived from billing codes rather than examination, and that will blur rather than manufacture the association.

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