Second to fourth digit ratio and lung function (forced vital capacity): predictors of maximum urinary flow rate after holmium laser enucleation of the prostate

Abstract

Background Maximum urinary flow rate (Qmax) is usually increased after holmium laser enucleation of the prostate (HoLEP). However, improvements vary between patients and results regarding potential predictors of Qmax after HoLEP are inconsistent. Thus, we investigated pre-operative variables including second to fourth digit ratio (digit ratio) and pulmonary function test (PFT) findings as potential predictors of Qmax after HoLEP. Methods One hundred and ninety-five consecutive patients with benign prostatic hyperplasia (BPH) who underwent HoLEP were enrolled. Before HoLEP, PFTs were performed and lengths of second and fourth digits of right hands were measured by a single investigator using a digital vernier caliper. To identify independent predictors of Qmax after HoLEP, univariate and multivariate analyses were performed using linear regression models. Results Mean age and total prostate volume for all 195 study subjects were 69.4 years and 63.3 mL respectively. Mean pre-operative and post-operative Qmax values were 8.7 and 26.2 mL/sec respectively. Univariate analysis showed age (r = -0.181, p = 0.014), digit ratio (r = 0.213, p = 0.004), lung function (forced vital capacity (FVC): r = 0.218, p = 0.005; forced expiratory volume in 1 sec (FEV1): r = 0.166, p = 0.034), pre-operative Qmax (r = 0.264, p = 0.000), pre-operative voided volume (VV) (r = 0.158, p = 0.033), and post-operative VV (r = 0.311, p = 0.000) were associated with post-operative Qmax, whereas multivariate analysis showed that digit ratio (beta = 0.285, p = 0.001), FVC (beta = 0.340, p = 0.039), and post-operative VV (beta = 0.301, p = 0.000) independently predicted post-operative Qmax. Conclusions The independent predictors of Qmax after HoLEP were digit ratio and lung function (FVC) as well as post-operative VV. This means that the higher a man's digit ratio and lung function (FVC), the higher his Qmax after HoLEP.