The diagnostic accuracy of spirometry as screening tool for adult patients with a benign subglottic stenosis.

BACKGROUND: There is a considerable diagnostic delay in the diagnosis 'benign acquired subglottic stenosis in adults' (SGS, diagnosed by the reference standard, i.e. laryngo- or bronchoscopy). Patients are frequently misdiagnosed since symptoms of this rare disease may mimic symptoms of 'asthma.' The 'Expiratory Disproportion Index' (EDI) obtained by spirometry, may be a simple instrument to detect an SGS-patient. The aim of this study was to evaluate the diagnostic accuracy of the EDI in differentiating SGS patients from asthma patients. METHODS: We calculated the EDI from spirometry results of all SGS-patients in the Leiden University Medical Center (LUMC), who had not received treatment 2 years before their spirometry examination. We compared these EDI results with the EDI results of all true asthma patients between 2011 and 2019, who underwent a bronchoscopy (exclusion of SGS by laryngo- or bronchoscopy). RESULTS: Fifty patients with SGS and 32 true asthma patients were included. Median and IQR ranges of the EDI for SGS and asthma patients were 67.10 (54.33-79.18) and 37.94 (32.41-44.63), respectively. Area under the curve (ROC) of the accuracy of the EDI at discriminating SGS and asthma patients was 0.92 (95% CI = 0.86-0.98). The best cut-off point for the EDI was > 48 (i.e. possible upper airway obstruction), with a sensitivity of 88.0%% (95%CI = 77.2-95.0%%) and specificity of 84.4% (95%CI = 69.4-94.1%). CONCLUSIONS: The EDI has a good diagnostic accuracy discriminating subglottic stenosis patients from asthma patients, when compared to the reference standard. This measurement from spirometry may potentially shorten the diagnostic delay of SGS patients. Further studies are needed to evaluate clinical reproducibility.

Practice variation in surgical treatment for lumbar degenerative disc disease: exploring regional and hospital factors influencing surgical rates.

The presence of significant, unwarranted variation in treatment suggests that clinical decision making also depends on where patients live instead of what they need and prefer. Historically, high practice variation in surgical treatment for lumbar degenerative disc disease (LDDD) has been documented. This study aimed to investigate current regional variation in surgical treatment for sciatica resulting from LDDD. We conducted a retrospective, cross-sectional analysis of all Dutch adults (>18 years) between 2016 and 2019. Demographic data from Statistics Netherlands were merged with a nationwide claims database, covering over 99% of the population. Inclusion criteria comprised LDDD diagnosis codes and relevant surgical codes. Practice variation was assessed at the level of postal code areas and hospital service areas (HSAs). Multivariable logistic regression analysis was employed to identify variables associated with surgical treatment. Among the 119,148 hospital visitors with LDDD, 14,840 underwent surgical treatment. Practice variation for laminectomies and discectomies showed less than two-fold variation in both postal code and HSAs. However, instrumented fusion surgery demonstrated a five-fold variation in postal code areas and three-fold variation in HSAs. Predictors of receiving surgical treatment included opioid prescription and patient referral status. Gender differences were observed, with males more likely to undergo laminectomy or discectomy, and females more likely to receive instrumented fusion surgery. Our study revealed low variation rates for discectomies and laminectomies, while indicating a high variation rate for instrumented fusion surgery in LDDD patients. High-quality research is needed on the extent of guideline implementation and its influence on practice variation.

Practice Variation Research in Degenerative Lumbar Disc Surgery: A Literature Review on Design Characteristics and Outcomes.

STUDY DESIGN: Literature review. OBJECTIVE: To describe whether practice variation studies on surgery in patients with lumbar degenerative disc disease used adequate study methodology to identify unwarranted variation, and to inform quality improvement in clinical practice. Secondary aim was to describe whether variation changed over time. METHODS: Literature databases were searched up to May 4th, 2021. To define whether study design was appropriate to identify unwarranted variation, we extracted data on level of aggregation, study population, and case-mix correction. To define whether studies were appropriate to achieve quality improvement, data were extracted on outcomes, explanatory variables, description of scientific basis, and given recommendations. Spearman's rho was used to determine the association between the Extreme Quotient (EQ) and year of publication. RESULTS: We identified 34 articles published between 1990 and 2020. Twenty-six articles (76%) defined the diagnosis. Prior surgery cases were excluded or adjusted for in 5 articles (15%). Twenty-three articles (68%) adjusted for case-mix. Variation in outcomes was analyzed in 7 articles (21%). Fourteen articles (41%) identified explanatory variables. Twenty-six articles (76%) described the evidence on effectiveness. Recommendations for clinical practice were given in 9 articles (26%). Extreme Quotients ranged between 1-fold and 15-fold variation and did not show a significant change over time (rho= -.33, P= .09). CONCLUSIONS: Practice variation research on surgery in patients with degenerative disc disease showed important limitations to identify unwarranted variation and to achieve quality improvement by public reporting. Despite the availability of new evidence, we could not observe a significant decrease in variation over time.