POSSIBILITIES FOR ANTIHYPERTENSIVE DRUG-THERAPY WITHDRAWAL IN THE ELDERLY

The aims of this study were to determine: (1) the proportion of elderl y hypertensive subjects currently attending a hospital hypertension cl inic suitable for a trial of antihypertensive durg withdrawal, (2) the proportion of suitable patients who can be successfully withdrawn fro m drug therapy while receiving nonpharmacological advice, and (3) the factors associated with successful withdrawal. One hundred and five co nsecutive hypertensive subjects, 53% female, mean age 76 years (range 65-84 years) on pharmacological antihypertensive therapy for >1 year w ere studied, of whom 78 (74%) had a clinic SBP <175 mmHg and DBP <100 mmHg. Subjects with recent myocardial infarction or stroke or with sym ptoms of ischaemic heart disease were excluded. Antihypertensive drug therapy was withdrawn in this group and nonpharmacological advice to l ower BP was instituted. Clinic BP and weight were subsequently recorde d monthly for 12 months in all subjects and at every three months in t hose who had a possible follow-up period of 24 months.; The 24h ambula tory BP was measured at baseline and repeated one month off therapy; 2 4h urine electrolytes were also assessed at baseline and at 12 months or before restarting drug therapy. Seventy-four (70%) subjects had a p otential follow-up of 12 months (four were withdrawn from the study) a nd 64 were available for two years of follow-up. Antihypertensive trea tment was restarted if SBP greater than or equal to 160 mmHg and/or DB P greater than or equal to 90 mmHg on two consecutive visits. After 12 months, 20 (25%) of those withdrawn remained normotensive. the majori ty restarting therapy did so in the first three months. Of the 64 subj ects followed up for two years, 13 (20%) remained normotensive. Logist ic regression analysis revealed a lower: (1) on treatment clinic and 2 4h SBP, (2) ECG (sV1 + rV6) voltage, and (3) BMI at baseline were pred ictors of those who would remain off therapy at one year. After 12 mon ths of nonpharmacological advice weight fell in subjects with BMI grea ter than or equal to 26 kg/m(2) by 2.6+/-4.8 kg; P<0.05. The 24h urina ry sodium and potassium excretion did not change significantly but the re was an increase in the potassium:creatinine ratio from 7.0+/-2.2 to 8.5+/-3.2 after 12 months, P<0.01. Following antihypertensive drug wi thdrawal and nonpharmacological advice 25% of elderly hypertensives ca n remain off drug treatment for greater than or equal to 12 months wit h good BP control. A long-term randomised trial is now required to ass ess specifically the contribution of nonpharmacological measures in re ducing the need for reintroduction of drug therapy in the elderly foll owing antihypertensive treatment withdrawal.