Work-exacerbated asthma and occupational asthma: do they really differ?

BACKGROUND: Although work-exacerbated asthma (WEA) is a prevalent condition likely to have an important societal burden, there are limited data on this condition. OBJECTIVES: The aims of this study were (1) to compare the clinical, functional, and inflammatory characteristics of workers with WEA and occupational asthma (OA) and (2) compare health care use and related costs between workers with WEA and OA, as well as between workers with work-related asthma (WRA; ie, WEA plus OA) and those with non-work-related asthma (NWRA) in a prospective study. METHODS: We performed a prospective observational study of workers with and without WRA with a 2-year follow-up. The diagnosis of OA and WEA was based on the positivity and negativity of results on specific inhalation challenges, respectively. RESULTS: One hundred fifty-four subjects were enrolled: 53 with WEA, 68 with OA, and 33 control asthmatic subjects (NWRA). WEA was associated with more frequent prescriptions of inhaled corticosteroids (odds ratio [OR], 4.4; 95% CI, 1.4-13.6; P = .009), a noneosinophilic phenotype (OR, 0.3; 95% CI, 0.1-0.9; P = .04), a trend toward a lower FEV1 (OR, 0.9; 95% CI, 0.9-1.0; P = .06), and a higher proportion of smokers (OR, 2.5; 95% CI, 0.96-9.7; P = .06) than the diagnosis of OA. The health care use of WRA and related costs were 10-fold higher than those of NWRA. CONCLUSION: Workers with WEA appeared to have features of greater asthma severity than workers with OA. In contrast with OA, WEA was associated with a noneosinophilic phenotype. Both OA and WEA were associated with greater health care use and 10-fold higher direct costs than NWRA.

Cost-effectiveness of various diagnostic approaches for occupational asthma.

BACKGROUND: Diagnosis of occupational asthma (OA) by specific inhalation challenge (SIC) can be costly and is not always available. The use of sputum testing to avoid this in some patients may be a more cost-effective alternative. OBJECTIVES: To compare the cost-effectiveness of SIC with serial measurements of sputum cell counts (sputum testing) and peak expiratory flow (PEF) monitoring. METHODS: Clinical data and testing costs for OA in 49 patients were collected during a previously published trial, modelled and compared using TreeAge Pro. Clinical outcome was the percentage of accurately diagnosed patients, using SIC as the gold standard. The PEF approach used the most accurate assessment of five experts who were blinded to SIC results. Differences in the proportion of eosinophils during periods on and off work were used for the sputum testing approach and in PEF/sputum for the combined approach. Unit costs were estimated from charges in Canadian hospitals. Data were analyzed by one-way and two-way analyses, and by probabilistic sensitivity analysis using a Monte Carlo simulation technique. RESULTS: The PEF approach had an estimated accuracy of 52% and cost $365 per patient tested. Compared with PEF monitoring, sputum testing was more accurate and cost an estimated $255 for each additional OA patient correctly diagnosed. SIC costs per additional correct diagnosis were $11,032 compared with sputum testing and $6,458 compared with PEF monitoring. The combined PEF/sputum testing approach was not cost-effective in the base case analysis, but cannot be excluded according to probabilistic sensitivity analyses. CONCLUSIONS: Although SIC remains the reference test to diagnose OA, when this test is not available, sputum testing is a cost-effective alternative to PEF for diagnosis of OA.

A one-year economic evaluation of six alternative strategies in the management of uninvestigated upper gastrointestinal symptoms in Canadian primary care.

BACKGROUND: The cost-effectiveness of initial strategies in managing Canadian patients with uninvestigated upper gastrointestinalsymptoms remains controversial. OBJECTIVE: To assess the cost-effectiveness of six management approaches to uninvestigated upper gastrointestinal symptoms in the Canadian setting. METHODS: The present study analyzed data from four randomized trials assessing homogeneous and complementary populations of Canadian patients with uninvestigated upper gastrointestinal symptoms with comparable outcomes. Symptom-free months, qualityadjusted life-years (QALYs) and direct costs in Canadian dollars of two management approaches based on the Canadian Dyspepsia Working Group (CanDys) Clinical Management Tool, and four additional strategies (two empirical antisecretory agents, and two prompt endoscopy) were examined and compared. Prevalence data, probabilities, utilities and costs were included in a Markov model, while sensitivity analysis used Monte Carlo simulations. Incremental cost-effectiveness ratios and cost-effectiveness acceptability curves were determined. RESULTS: Empirical omeprazole cost $226 per QALY ($49 per symptom-free month) per patient. CanDys omeprazole and endoscopy approaches were more effective than empirical omeprazole, but more costly. Alternatives using H2-receptor antagonists were less effective than those using a proton pump inhibitor. No significant differences were found for most incremental cost-effectiveness ratios. As willingness to pay (WTP) thresholds rose from $226 to $24,000 per QALY, empirical antisecretory approaches were less likely to be the most costeffective choice, with CanDys omeprazole progressively becoming a more likely option. For WTP values ranging from $24,000 to $70,000 per QALY, the most clinically relevant range, CanDys omeprazole was the most cost-effective strategy (32% to 46% of the time), with prompt endoscopy-proton pump inhibitor favoured at higher WTP values. CONCLUSIONS: Although no strategy was the indisputable cost effective option, CanDys omeprazole may be the strategy of choiceover a clinically relevant range of WTP assumptions in the initial management of Canadian patients with uninvestigated dyspepsia.

Health survey data on potentially inappropriate geriatric drug use.

BACKGROUND: Studies have suggested that elderly patients do not always use medications appropriately. Investigations that have relied on prescription claim databases or clinical records focus on acquisition or prescription, and hypotheses must be made to assess actual consumption. Population survey data constitute an altemative way to study inappropriate use. OBJECTIVE: To estimate the prevalence of potentially inappropriate use of medications in elderly patients in Québec based on self-reported use. METHODS: Using a cross-sectional, general population, health survey in which self-reported medication use in the 2 days prior to the survey was recorded, we estimated the prevalence of inappropriate medication use in elderly patients (> or =65 y old) who responded. Two sets of published criteria were used to define inappropriate use: one to assess use of inappropriate drugs, and another to assess concomitant duplications and potential interactions. RESULTS: Of the 3400 patients surveyed, 6.5% had used > or =1 inappropriate drugs, 2.5% had > or =1 occurrences of potentially inappropriate duplication of medications, and 2.7% had > or =1 potential medication interactions. Concomitant use of at least 2 benzodiazepines was reported by 8.5% of respondents using these drugs. Use of > or =1 long-acting benzodiazepines was reported by 4.2% of the sample. CONCLUSIONS: Population health surveys are a useful tool for detecting potentially inappropriate medication use in the elderly. In particular, the high prevalence of inappropriate use of benzodiazepines signals a need for improved detection and intervention in this group.

Does clinical trial subject selection restrict the ability to generalize use and cost of health services to "real life" subjects?

OBJECTIVES: To explore one aspect of the external validity of the randomized controlled trial (RCT), specifically how being selected for inclusion in a trial and having participated has influenced the use and cost of asthma-related health services. METHODS: Services used by asthmatic users of inhaled corticosteroids (iCSTs) having previously participated in an RCT (TS, n = 46) were compared with individuals who had never participated (NS, n = 51). RESULTS: TS were more likely to use higher (> or = 400 microg) daily doses of iCSTs than NS (OR, 3.3; 95% Cl, 1.1-8.3) but less likely to visit emergency departments (OR, 0.3; 95% Cl, 0.1-0.7). Total asthma-related costs did not differ significantly. CONCLUSIONS: Subject differences may impede generalizing from RCTs to real life.