Urinary fluticasone propionate-17beta-carboxylic acid to assess asthma therapy adherence

Although the National Asthma Education and Prevention Program Expert Panel Report 3 recommends referral to specialists to address adherence, guidelines do not provide a tool to determine nonadherence. This study was designed to prospectively evaluate the characteristics of urinary analysis of fluticasone propionate-17beta-carboxylic acid (FP17betaCA) as a test to verify if a specific patient has not taken fluticasone propionate (FP) within 16‐24 hours. Urine of asthmatic subjects was prospectively analyzed 16‐24 hours after witnessed administration of orally inhaled FP using liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis; limit of quantitation was 10.3 pg/mL. Results were compared with those from asthmatic subjects not receiving inhaled FP. Thirty asthmatic subjects receiving inhaled FP (2 oral inhalations of FP at 110 micrograms each or 1 oral inhalation twice daily of fluticasone and salmeterol in fixed combination at 250/50 micrograms for 1 week) were compared with 30 asthmatic subjects not receiving FP. FP17betaCA was detected in the urine of 30 of 30 asthmatic subjects receiving FP (median, interquartile range [IQR; 413.5, 212.8‐1230.0] range 12.4‐3290.0 pg/mL [corrected for urine creatinine: median, IQR {576.2, 188.1‐1306.6} range 6.3‐5425.9 ng/g Cr]) and was undetectable in 30 of 30 subjects not receiving inhaled FP. The sensitivity and specificity of LC-MS/MS to detect FP17betaCA in urine were 100% (95% exact binomial confidence interval, 88‐100) and 100% (95% exact binomial confidence interval, 88‐100), respectively. Analysis of FP17betaCA in urine provides a sensitive method that may be used to verify that a specific patient may not have administered FP within a 16- to 24-hour window before testing.