Effect of Parathyroidectomy Upon Left Ventricular Mass in Primary Hyperparathyroidism: A Meta-Analysis

Context: Primary hyperparathyroidism (PHPT) has been associated with increased left ventricular mass (LVM) in many studies. Most studies have been inadequately powered to assess the effect of parathyroidectomy (PTX) on LVM. Objective: The objective was to evaluate whether PTX has a benefit on LVM in patients with PHPT. Data Sources: Sources included PubMed, Medline, Cochrane Library, clinicaltrials.gov, review articles, and abstracts from meetings. Study Selection: Eligible studies included prospective studies of PTX vs observation or PTX alone in patients with PHPT who had LVM measured by echocardiography. Data Extraction: Two investigators independently identified eligible studies and extracted data. Random-effects models were used to obtain final pooled estimates. Data Synthesis: Fifteen studies (four randomized controlled trials and 11 observational) of 457 participants undergoing PTX were included. PTX was associated with a reduction in LVM (crude Hedges g(u) -0.290 +/- 0.070, 95% confidence interval [CI] -0.423 to -0.157) of 11.6 g/m(2) (12.5%) on average. Effect size estimates differed by study duration (P < .001), with improvements seen in shorter (<= 6 mo) but not longer studies. There was a trend toward greater improvement in observational studies vs randomized controlled trials (P = .07), and both serum calcium and PTH were higher in the former. Using random-effects models, the estimated effect size remained significant (Hedges g(u) -0.250, 95% CI -0.450 to -0.050). Higher preoperative PTH but not calcium was associated with a greater decline in LVM (beta = -.039, 95% CI -0.075 to -0.004). Conclusion: PTX reduced LVM in PHPT, and higher preoperative PTH levels were associated with greater improvements. Because the benefit was limited to short-term studies and PHPT disease severity was not independent of study design, further work is needed to clarify the factors that influence the change in LVM and whether the benefit persists beyond 6 months after PTX. Although the clinical significance of the LVM improvement is unclear, these data indicate that PTH may underlie increased LVM in PHPT.