Immediate septoplasty was more costly but produced greater gains in quality-adjusted life years than initial medical management among adults with nasal obstruction associated with a deviated septum, according to an economic evaluation published in BMJ Open. At 12 months, its probability of being cost-effective depended heavily on how surgical costs were estimated; a model extending the findings to 24 months favored immediate surgery, although it remained more costly overall.
Researchers conducted the economic evaluation alongside the multicenter, open-label Nasal AIRway Obstruction Study randomized controlled trial. The analysis included 307 adults with at least moderate nasal obstruction associated with septal deviation, defined as a Nasal Obstruction and Symptom Evaluation score greater than 30. Patients were recruited at 17 otolaryngology clinics in England, Scotland, and Wales from January 2018 through December 2019.
Patients were randomly assigned 1:1, with stratification by sex and baseline symptom severity, to undergo septoplasty within 12 weeks or receive 6 months of mometasone nasal spray and saline spray, followed by the option for delayed septoplasty. By 12 months, 148 of 152 patients assigned to immediate surgery and 47 of 155 patients assigned to initial medical management had undergone septoplasty.
The primary economic outcome was the incremental cost per quality-adjusted life year gained at 12 months from a UK National Health Service and personal social services perspective. Costs were reported in 2020 British pounds. Quality-adjusted life years were calculated from Short Form 6 Dimensions utility scores mapped from patients’ Short Form-36 responses.
Incremental costs and quality-adjusted life years were estimated with seemingly unrelated regression adjusted for age, sex, ethnicity, baseline Sino-Nasal Outcome Test-22 score, and baseline utility. Because questionnaire responses were missing for up to 30% of patients at 12 months, the base-case analysis used chained multiple imputation.
At 12 months, estimated mean health care costs were £2,162 with immediate septoplasty and £973 with initial medical management. Immediate septoplasty was associated with an adjusted incremental cost of £1,193 and an additional 0.044 quality-adjusted life years, producing an incremental cost-effectiveness ratio of £27,114 per quality-adjusted life year.
Using the National Health Service tariff to price surgery, immediate septoplasty had a 15% probability of being cost-effective at a willingness-to-pay threshold of £20,000 per quality-adjusted life year. The researchers concluded that immediate surgery was unlikely to meet that threshold at 12 months under the base-case costing approach.
The result was sensitive to the estimated cost of septoplasty. When investigators used patient-level micro-costing rather than the national tariff, the incremental cost-effectiveness ratio decreased to £16,682 per quality-adjusted life year, and the probability of cost-effectiveness increased to approximately 79%. However, the micro-costing analysis excluded some overhead expenses, used consumable-cost data from one site, and collected patient-level surgical resource data only among patients assigned to immediate septoplasty. As a result, variation in surgical costs among patients assigned to medical management who later underwent surgery was not captured fully in the bootstrap analysis.
Investigators also used a decision-tree model to extrapolate costs and outcomes through 24 months. Immediate septoplasty remained more costly by £833 and was associated with an additional 0.06 quality-adjusted life years, resulting in an incremental cost-effectiveness ratio of £13,221 per quality-adjusted life year. At the £20,000 threshold, the modeled probability of cost-effectiveness was 99%.
The 24-month analysis was not based on additional randomized follow-up. The model assumed that 15% of patients initially assigned to medical management would undergo septoplasty during the second year, that half of those who had not undergone surgery would resume nasal sprays, and that health care use and utility values after 12 months would remain similar to those observed during the final 6 months of the trial.
Health care utilization outside the assigned interventions was similar between groups during the first 12 months, indicating that most of the cost difference was attributable to surgery and nasal spray treatment. The higher utility values among patients assigned to immediate septoplasty were consistent with disease-specific symptom improvements reported in the parent NAIROS trial.
The researchers cautioned that the 24-month analysis extrapolated data from a 12-month trial and relied on assumptions informed partly by clinical opinion. An as-treated sensitivity analysis was also limited by substantial imbalance after crossover, with 47 patients from the initial medical-management group and 4 from the immediate-surgery group included in the opposite treatment category. The researchers therefore used intention-to-treat as the primary approach to reduce potential bias and better reflect real-world effectiveness.
Because the analysis used UK National Health Service costs and a £20,000-per-QALY threshold, its economic estimates may not translate directly to US reimbursement and practice settings.
“Immediate septoplasty is more costly but more effective, in terms of QALYs gained, than 6 months of medical management with the option for deferred septoplasty in the management of deviated nasal septum,” wrote lead study author Tara Homer, of the Population Health Sciences Institute at Newcastle University in Newcastle upon Tyne, United Kingdom, and colleagues.
Disclosures: The study was funded by the National Institute for Health Research Health Technology Assessment Programme. The researchers reported no financial relationships with organizations that might have had an interest in the submitted work and no other relationships or activities that could appear to have influenced it. Janet A. Wilson was a member of the BMJ Open Editorial Board.
Source: BMJ Open