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.