THE PREVALENCE OF RESISTANT HYPERTENSION IN A LARGE OUTPATIENT 24 HOUR ABPM POPULATION
Author Block DW Armstrong, D Brouillard, M Matangi
BACKGROUND: Resistant hypertension is a common problem faced by Physicians. The exact prevalence of resistant hypertension is unknown, but clinical trials suggest a prevalence of anywhere from 20% to 30%. The purpose of our study was to determine the prevalence of resistant hypertension in patients presenting to the Kingston Heart Clinic for 24hr ambulatory blood pressure monitoring (ABPM).
METHODS: ABPMfile the 24hr blood pressure module of CARDIOfile was interrogated for all patients whose drug therapy was also documented. Only the very first ABPM was used for each patient. Resistant hypertension was defined as an average daytime ABPM of >135mmHg in a patient taking at least 3 antihypertensive drugs. 12,881 patients had a single 24hr ABPM. Of these 12,881, 11,806 (91.6%) had all required data fields entered. ANOVA was used to assess overall differences between the means and Tukey-Kramer multiple comparisons testing was performed if the ANOVA level of significance was <0.05.
RESULTS: Of the 11,806 patients, 5,725 were on no antihypertensive treatment and 2889 (50.5%) of these patients were normotensive. Of the remaining 6,081 patients, 3,087 (51%) were normotensive on treatment. See Table 1.
CONCLUSION: Of the 1006 patients treated with either 3 or more antihypertensive agents 503 were classified as resistant hypertensives. The prevalence of resistant hypertension was 8.3% of the treated hypertensive population but 50% of those patients treated with 3 or more drugs. There was no significant difference between the mean daytime 24hr ABPM systolic blood pressure for patients treated with 1, 2, or ≥3 antihypertensive drugs using ANOVA.
|N||Uncontrolled daytime SBP >135mmHg||% uncontrolled||Average daytime SBP >135mmHg|
|No drugs||5725||2836||49.5||145.9 ± 8.7|
|1 drug||2838||1463||51.6||147.6 ± 10.0|
|2 drugs||2237||1028||46.0||148.2 ± 10.7|
|≥3 drugs||1006||503||50.0||148.8 ± 11.4|