Flushing ASsessment Tool (FAST): psychometric properties of a new measure assessing flushing symptoms and clinical impact of niacin therapy.

ABSTRACT

BACKGROUND AND OBJECTIVE: A common adverse effect of niacin therapy is flushing, manifested by cutaneous warmth, redness, itching and/or tingling. The Flushing ASsessment Tool (FAST) was developed to assess flushing symptoms and their impact on patients receiving niacin therapy. This study evaluated the reliability, validity and responsiveness of the FAST. The minimal important difference (MID) of the FAST was also examined. METHODS: This was a prospective, randomized, double-blind, placebo-controlled, parallel-group 8-week study conducted to evaluate the psychometric characteristics of the FAST. The instrument is administered daily using an electronic patient diary. The study was conducted at 41 clinical sites in the US. 276 patients with dyslipidaemia were randomized to treatment and were at least 18 years of age, with fasting laboratory values of low-density lipoprotein cholesterol (LDL-C) <250 mg/dL and one of the following high-density lipoprotein cholesterol (HDL-C) <40 mg/dL for males or <50 mg/dL for females; or triglycerides (TG) > or = 150 and < or = 400 mg/dL; or LDL-C > or = 70 mg/dL for patients with a history of coronary heart disease (CHD) or CHD risk equivalents, or > or = 100 mg/dL for subjects with two risk factors, or > or = 160 mg/dL for subjects with 0-1 risk factors. Patients were randomized (1 1 1) to receive niacin extended-release (NER) 500 mg/day in week 1, 1000 mg/day in week 2 and 2000 mg/day in weeks 3-6/aspirin (acetylsalicylic acid [ASA]), NER/ASA placebo, or NER placebo/ASA placebo. RESULTS: FAST test-retest reliability in stable patients during the first 2 weeks was demonstrated for overall flushing severity using patient and physician overall treatment effect (OTE) ratings (intraclass correlation coefficients of >0.7 for mean overall and individual flushing severity scores). Over the 6-week treatment period, FAST scores demonstrated significant correlations with individual symptoms, impact on daily activities and sleep, and dissatisfaction related to flushing (p < 0.01). Changes in FAST scores were associated with treatment satisfaction (p < 0.01) and patient- and physician-rated OTE (p < 0.01). Using patient-rated OTE, the mean maximum flushing severity scores improved 1.85 points in responders and only 0.18 points in non-responders (p < 0.001); responders were defined by improved patient- or physician-rated OTE. Among patients with flushing, mean maximum overall flushing scores differed between patients who subsequently discontinued due to flushing (7.9 points) and those who did not discontinue (4.7 points; p < 0.001). The probable range in this study for a detectable change in flushing symptoms (MID) was 0.29-0.38 points for mean flushing severity and 0.66-0.86 points for maximum flushing severity. CONCLUSION: The FAST exhibited test-retest reliability, good evidence of construct validity, and, overall, flushing severity was responsive to change over time. The FAST is a reliable and valid instrument for assessing the impact of niacin-induced flushing in patients with dyslipidaemia.