Association of smoking with phenotype at diagnosis and vascular interventions in patients with renal artery fibromuscular dysplasia.

The pathogenesis of fibromuscular dysplasia (FMD) remains unclear, but tobacco use is thought to be involved. This retrospective cross-sectional study aimed to evaluate smoking first as a risk factor for renal artery FMD diagnosis and second as a modifier of the clinical and radiological phenotype of this disease. We retrieved 337 adult patients diagnosed with FMD in a referral center for hypertension management, who were first individually matched to controls with essential hypertension for sex, age, systolic blood pressure, number of antihypertensive drugs, and year of visit. Smoking status and other relevant data were collected at first visit. The proportion of current smokers was higher for patients with FMD than for the controls (30% and 18%, respectively, P<0.001; odds ratio, 2.5 [95% confidence interval, 1.6-3.9]). Second, characteristics of FMD were compared between current smokers and other patients. Among patients with multifocal FMD, current smokers experienced an earlier diagnosis of hypertension (36 versus 42 years, respectively; P<0.001) and FMD (43 versus 51 years; P<0.001) than other patients, and a greater likelihood of renal artery interventions (57% versus 31%; P<0.001) and of kidney asymmetry (21% versus 4%; P=0.001). In conclusion, current smoking is associated with a higher likelihood of renal artery FMD diagnosis. Rather than a higher incidence of FMD, this may reflect a more aggressive course in smokers, who have earlier hypertension leading to increased and earlier recognition of the disease. Smoking cessation should be strongly encouraged in patients with FMD.