Aldosteronism linked to poor bone health

By Laura Cowen

Primary aldosteronism (PA) is associated with low bone mass, increased prevalence of osteoporosis, and vertebral fractures, Italian research shows.

Furthermore, compared with patients without PA, those with the condition have significantly increased urinary calcium (6.28 vs 4.28 mmol/day) and parathyroid hormone (PTH) (9.8 vs 5.3 pmol/L) levels, report Alfredo Scillitani (Ospedale "Casa Solievo della Sofferenza) and colleagues in the Journal of Bone and Mineral Research.

This indicates that "the observed skeletal involvement may be due, at least partially, to increased urinary calcium excretion and consequent secondary hyperparathyroidism," they remark.

The researchers evaluated bone involvement in patients with PA, a condition that has previously been linked to cardiovascular and renal injury, and altered calcium metabolism.

They initially screened 188 consecutive patients with adrenal incidentaloma for PA using the aldosterone-to-renin ratio (ARR), and identified 30 with suspected PA (ARR>65 pmol/L:pmol/L per minute). Of those 11 had confirmed PA, 15 did not have PA (nPA), and the remaining four did not continue with the study.

Dual energy X-ray absorptiometry showed that patients with PA had significantly lower bone mineral density (BMD) at the lumbar spine, and total and femoral neck compared with those without PA, and the prevalence of osteoporosis (T-score <-2.5 and/or presence ofnontraumatic vertebral fractures) was significantly higher in the PA group than in nPA group (72.7 vs 20.0%).

Vertebral fractures also tended to be more prevalent in the PA group than in the nPA group (45.5 vs 13.3%), but the difference was not statistically significant.

However, after adjustment for age, body mass index and lumbar spine BMD, patients with PA were a significant 30 times more likely to have morphometric vertebral fractures than those without PA.

PA patients were also a significant 15 times more likely to have osteoporosis than those without PA.

The researchers note that 6 months after treatment with surgery or a diuretic drug, nine of the 11 PA patients, showed a significant reduction in urinary calcium excretion and PTH, while five had significantly increased lumbar spine BMD after 1 year.

The team points out that the study sample was not representative of the broader PA population as the patients were only selected from a group with adrenal incidentaloma.

Even so, "we believe that aldosterone excess leads not only to cardiovascular and renal injury but also to bone damage," Scillitani and co-authors conclude.

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