Predictors of failure to initiate randomized treatment in a large trial of antihypertensive drug therapy in the aged.
BACKGROUND
The identification of factors that contribute to noncompliance with trial drug initiation where virtually complete compliance might be expected, may help identify patients whose management is least likely to comply with clinical guidelines and study protocols.


METHODS
Examination of cross-sectional and longitudinal data arising from the Second Australian National Blood Pressure Study. Prevalence rate ratios (RR) and 95% confidence intervals (CI) estimated from log-binomial models were used to assess associations between subject characteristics and whether the randomized drug was prescribed at trial randomization. The study population consisted of 6083 hypertensive Australians aged 65 to 84 years.


RESULTS
After adjusting for each variable in a multivariate model the following were significant predictors of failure to prescribe RR (95% CI): not previously prescribed antihypertensive drugs 2.89 (2.52-3.32); lower systolic blood pressure (BP) 1.51 (1.59-1.43) or diastolic BP 1.18 (1.22-1.13); younger age 80 to 84 v 65 to 79 years 0.75 (0.59-0.95); total cholesterol >or=6.6 v <or=5.0 mmol/L 1.27 (1.06-1.53); and not ever having had a raised cholesterol 1.20 (1.04-1.40). There was no difference in cardiovascular disease end points and death in those who were and were not initiated on drug therapy at randomization.


CONCLUSIONS
Failure to initiate antihypertensive therapy for patients at the randomization visit was associated with lower BP measurements, previous drug therapy, younger age, and a historic or current raised cholesterol, but not with overt cardiovascular disease or other risk factors. There was no difference in cardiovascular disease end points and death in those who were and were not initiated on drug therapy at randomization.
Nelson
Mark R
MR
Discipline of General Practice, University of Tasmania, Hobart, Australia. Mark.Nelson@utas.edu.au
Ryan
Philip
P
Willson
Kristyn
K
Reid
Christopher M
CM
Beilin
Lawrence J
LJ
Jennings
Garry L
GL
Johnston
Colin I
CI
Macdonald
Graham J
GJ
Marley
John E
JE
McNeil
John J
JJ
Morgan
Trefor O
TO
West
Malcolm J
MJ
Wing
Lindon M H
LM
D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000959:Antihypertensive Agents / Q000627:therapeutic use*; D001794:Blood Pressure; D003430:Cross-Sectional Studies; D011307:Drug Prescriptions / Q000592:standards; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006973:Hypertension / Q000188:drug therapy*; D008297:Male; D015999:Multivariate Analysis; D010349:Patient Compliance; D010817:Physician-Patient Relations; D010818:Practice Patterns, Physicians'; D011237:Predictive Value of Tests; D016032:Randomized Controlled Trials as Topic / Q000379:methods / Q000592:standards; D012307:Risk Factors
D000959:Antihypertensive Agents