A validation study of an esophageal probe-based polygraph against polysomnography in obstructive sleep apnea.

STUDY OBJECTIVES: The aim of this study was to validate the automatically scored results of an esophageal probe-based polygraph system (ApneaGraph® Spiro) against manually scored polysomnography (Nox A1, PSG) results. We compared the apnea-hypopnea index, oxygen saturation index, and respiratory disturbance index of the devices. METHODS: Consenting patients, referred for obstructive sleep apnea workup, were tested simultaneously with the ApneaGraph® Spiro and Nox A1® polysomnograph. Each participant made one set of simultaneous registrations for one night. PSG results were scored independently. Apnea-hypopnea index, oxygen desaturation index, and respiratory disturbance index were compared using Pearson's correlation and scatter plots. Sensitivity, specificity, and positive likelihood ratio of all indices at 5, 15, and 30 were calculated. RESULTS: A total of 83 participants had successful registrations. The apnea-hypopnea index showed sensitivity of 0.83, specificity of 0.95, and a positive likelihood ratio of 5.11 at an index cutoff of 15. At a cutoff of 30, the positive likelihood ratio rose to 31.43. The respiratory disturbance index showed high sensitivity (> 0.9) at all cutoffs, but specificity was below 0.5 at all cutoffs. Scatterplots revealed overestimation in mild OSA and underestimation in severe OSA for all three indices. CONCLUSIONS: The ApneaGraph® Spiro performed acceptably when OSA was defined by an AHI of 15. The equipment overestimated mild OSA and underestimated severe OSA, compared to the PSG.

Does a surgeon's annual radical prostatectomy volume predict the risk of positive surgical margins and urinary incontinence at one-year follow-up? Findings from a prospective national study.

OBJECTIVE: This study aimed to assess the prevalence of positive surgical margins (PSM) and urinary incontinence (UI) in relation to surgeons' annual radical prostatectomy (RP) volume. MATERIAL AND METHODS: This national study prospectively assessed 521 preoperatively continent patients with prostate cancer (PCa), scheduled for RP by surgeons with high (>50), medium (20-50) or low annual volume (<20) at 14 urological departments in Norway. Patients responded to UI questions from the Expanded Composite prostate cancer index (EPIC-50) before and 1 year after RP. UI was defined as "use of pad(s)" and/or "a moderate or severe urinary leakage problem (ULP)". Preoperative prediction of PSMs and UI was explored in multivariate regression analyses with the following independent variables: surgeons' annual RP volume, type of hospital (university versus community), patient's health, sociodemographic features and PCa characteristics. RESULTS: Based on histopathological reports, the overall PSM rate was 26%, with differences between the high- (18%), medium- (28%) and low-volume (44%) groups. Increasing PSM rates were predicted by surgeons belonging to the low- and medium-volume categories, prostate-specific antigen> 10 µg/l, Gleason score >7, patient age >65 years and <12 years of education. At 1-year follow-up 40% reported UI, without significant differences between the volume groups. Only 46% of those who used pad(s) experienced ULP. UI was predicted by clinical category ≥T2 and community type of hospital, but not by surgeons' annual RP volume. CONCLUSIONS. Preoperative counselling should take into account the relationship between surgeon's annual RP volume and PSM rate and the current knowledge about UI and ULP.