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Trial of Antihypertensive Interventions and Management - TAIM
Description:
TAIM was a multi-center, randomized trial to examine the diastolic blood pressure response of various combinations of pharmacologic and dietary interventions.
Hypothesis:
Different combinations of dietary and pharmacologic intervention have differing effects on diastolic blood pressure.
Study Design
Study Design:
Patients Screened: 10148
Patients Enrolled: 881
Mean Follow Up: 6 months
Mean Patient Age: 21-65
Female: 44
Patient Populations:
Men and women aged 21-65 years. Diastolic hypertension (DBP>100mmHg for participants currently on antihypertensives or DBP 90-104mmHg for those not on medication).
Exclusions:
Patients less than 110% or more than 160% ideal body weight. History of MI, stroke, or bronchial asthma. Creatinine level >180μmol/l. Diabetes requiring insulin. Allergy to thiazides or beta blockers. Actual or contemplated pregnancy.
Primary Endpoints:
Change in diastolic blood pressure at 6 months.
Secondary Endpoints:
Change in systolic blood pressure, sodium excretion, and weight at six months.
Drug/Procedures Used:
The study was a 3x3 factorial design consisting of three drug and three diet groups. For drug therapy, participants received either placebo, diuretic (chlortalidone 25mgqd), or beta blocker (atenolol 50mg qd). For dietary intervention patients received either usual diet (no change), weight loss diet (goal weight reduction of 10% of baseline weight), or low salt/high potassium diet (average sodium 87mmol/day, average potassium 103mmol/day). Drug therapy was administered in a double blind fashion.
Concomitant Medications:
No other antihypertensives allowed.
Principal Findings:
TAIM randomized 878 patients into nine groups consisting of different combinations of diet and drug therapy. At baseline the groups were well matched in terms of age, gender, weight, comorbidities, and blood pressure. Attainment of dietary goals was high as evidenced by the average weight loss 4.7kg for patients on the weight loss diet and an average decrease in urinary sodium of 27.4mm/day in the low sodium/high potassium diet arm.
For the primary endpoint, change in diastolic blood pressure at 6 months, the largest decrease occurred in the weight loss/diuretic (-15.06 mmHg) and weight loss/beta blocker (-14.81 mmHg) arms. The diet/placebo subgroups all exhibited a similar drop in diastolic blood pressure (~8mmHg). Two way analysis of variance showed that the main effects of diet and drug therapy were highly significant (p<0.001) but there was no significant interaction term. In head to head comparisons, the weight loss diet lowered DBP significantly more than usual diet. Either diuretic or beta blocker was significantly better than placebo. The usual diet and low salt/high potassium diet had similar effects on blood pressure. There was no difference in effect on blood pressure between diuretic and beta blocker treatment.
Interpretation:
Among patients with diastolic hypertension, a successful weight loss program showed additional benefit to treatment with diuretics or beta blockers. A low salt/high potassium diet was not associated with additional blood pressure reduction compared to usual diet.
References:
Langford HG, Davis BR, Blaufox D, Oberman A, Wassertheil-Smoller S, Hawkins M, Zimbaldi N. Effect of drug and diet treatment of mild hypertension on diastolic blood pressure. The TAIM Research Group. Hypertension. 1991 Feb;17(2):210-7.
Keywords: Chlorthalidone, Diuretics, Comorbidity, Diet, Reducing, Potassium, Drug Combinations, Diet, Sodium-Restricted, Weight Reduction Programs, Hypertension
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