TY - JOUR
T1 - Co-calibration of two self-reported measures of adherence to antiretroviral therapy
AU - Nance, Robin M.
AU - Delaney, J. A.Chris
AU - Golin, Carol E.
AU - Wechsberg, Wendee M.
AU - Cunningham, Chinazo
AU - Altice, Frederick
AU - Christopoulos, Katerina
AU - Knight, Kevin
AU - Quan, Vu
AU - Gordon, Michael S.
AU - Springer, Sandra
AU - Young, Jeremy
AU - Crane, Paul K.
AU - Mayer, Kenneth H.
AU - Mugavero, Michael J.
AU - Del Rio, Carlos
AU - Kronmal, Richard A.
AU - Crane, Heidi M.
N1 - Publisher Copyright:
© 2016 Informa UK Limited, trading as Taylor & Francis Group.
PY - 2017/4/3
Y1 - 2017/4/3
N2 - Adherence to antiretroviral therapy (ART) is an important determinant of clinical success assessed in many HIV studies. Harmonizing adherence data from studies that use different measures is difficult without a co-calibration equation to convert between validated instruments. Our purpose was to co-calibrate two commonly used adherence measures: the AIDS Clinical Trials Group (ACTG) questionnaire and the Visual Analog Scale (VAS). We used robust linear regression to develop a co-calibration equation in a clinical care cohort. The outcome was the 30-day VAS percentage of ART taken and the predictors were ACTG questions. We evaluated the equation’s goodness of fit in five STTR (Seek, Test, Treat, Retain) consortium studies where individuals completed both measures: 2 criminal justice; 2 international; and 1 other high-risk vulnerable population. We developed a three-phase decision rule to convert ACTG to VAS in 1045 participants. First, when the last missed dose on the ACTG was reported as >30 days ago, the VAS was set to 100% (N = 582). Second, if “doses missed” was zero for all items, VAS was 100% (N = 104). Third, among remaining participants (N = 359), VAS was estimated as 96.8% minus 2.9% times the number of missed doses (“doses per day” was non-significant). Correlation between predicted and reported VAS was r = 0.80 in the criminal justice group (N = 446), r = 0.46 in the international group (N = 311), r = 0.32 in the other vulnerable population (N = 63), and r = 0.66 overall. When outliers due to inversion of the VAS scale were excluded (n = 25), these correlations were 0.88, 0.78, 0.80, and 0.86, respectively. We concluded that a simple decision rule and equation allowed us to co-calibrate between two widely used adherence measures thus combining data from studies with different instruments. This study highlighted issues with VAS inversions and its limitations as a single item. Combining studies using different instrument facilitates larger pooled datasets to address key research questions.
AB - Adherence to antiretroviral therapy (ART) is an important determinant of clinical success assessed in many HIV studies. Harmonizing adherence data from studies that use different measures is difficult without a co-calibration equation to convert between validated instruments. Our purpose was to co-calibrate two commonly used adherence measures: the AIDS Clinical Trials Group (ACTG) questionnaire and the Visual Analog Scale (VAS). We used robust linear regression to develop a co-calibration equation in a clinical care cohort. The outcome was the 30-day VAS percentage of ART taken and the predictors were ACTG questions. We evaluated the equation’s goodness of fit in five STTR (Seek, Test, Treat, Retain) consortium studies where individuals completed both measures: 2 criminal justice; 2 international; and 1 other high-risk vulnerable population. We developed a three-phase decision rule to convert ACTG to VAS in 1045 participants. First, when the last missed dose on the ACTG was reported as >30 days ago, the VAS was set to 100% (N = 582). Second, if “doses missed” was zero for all items, VAS was 100% (N = 104). Third, among remaining participants (N = 359), VAS was estimated as 96.8% minus 2.9% times the number of missed doses (“doses per day” was non-significant). Correlation between predicted and reported VAS was r = 0.80 in the criminal justice group (N = 446), r = 0.46 in the international group (N = 311), r = 0.32 in the other vulnerable population (N = 63), and r = 0.66 overall. When outliers due to inversion of the VAS scale were excluded (n = 25), these correlations were 0.88, 0.78, 0.80, and 0.86, respectively. We concluded that a simple decision rule and equation allowed us to co-calibrate between two widely used adherence measures thus combining data from studies with different instruments. This study highlighted issues with VAS inversions and its limitations as a single item. Combining studies using different instrument facilitates larger pooled datasets to address key research questions.
KW - Adherence
KW - HIV
KW - antiretroviral therapy
KW - calibration
KW - visual analog scale
UR - http://www.scopus.com/inward/record.url?scp=85000949432&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85000949432&partnerID=8YFLogxK
U2 - 10.1080/09540121.2016.1263721
DO - 10.1080/09540121.2016.1263721
M3 - Article
C2 - 27910703
AN - SCOPUS:85000949432
SN - 0954-0121
VL - 29
SP - 464
EP - 468
JO - AIDS Care - Psychological and Socio-Medical Aspects of AIDS/HIV
JF - AIDS Care - Psychological and Socio-Medical Aspects of AIDS/HIV
IS - 4
ER -
