Prevalence and determinants of apparent treatment-resistant hypertension among patients in South African primary care: a single-centre observational study

Govender, Kellicia Courtney; Naidoo, Mergan

doi:10.1186/s12872-025-04813-6

Table 1 Baseline demographic, anthropometric, and blood pressure characteristics of people living with hypertension

From: Prevalence and determinants of apparent treatment-resistant hypertension among patients in South African primary care: a single-centre observational study

Variable	Total N = 400	No aTRH N = 325	aTRH N = 75	p-value	Uncontrolled aTRH N = 44	Controlled aTRH N = 31	p-value
*Demographics*
Age (years) mean(± SD)	64.4 (10.8)	64.2(10.7)	65.4(11.1)	0.383	63.5(11.5)	68.1(10.0)	0.074
Age category, n (%)
30–39	4 (1.0)	4 (1.2)	0 (0)	1.00	0(0)	0(0)
40–49	30 (7.5)	22(6.8)	8(10.7)	0.248	6(13.6)	2(6.5)	0.457
50–59	94 (23.5)	78 (24.0)	16(21.3)	0.623	10(22.7)	6(19.4)	0.782
60–69	139 (34.8)	117 (36.0)	22(29.3)	0.274	13(29.5)	9(29.0)	0.962
70–79	100(25.0)	79 (24.3)	21(28.0)	0.506	11(25.0)	10(32.3)	0.475
80–89	32(8.0)	25 (7.7)	7(9.3)	0.637	4(9.1)	3(9.7)	0.931
90–99	1(0.3)	0 (0)	1(1.3)	0.187	0(0)	1(3.2)	0.230
Gender n (%)
Female	260(65.0)	213(65.5)	47(62.7)	0.638	30(68.2)	17(54.8)	0.239
Ethnicity, n (%)
Caucasian	54(13.5)	46(14.2)	8(10.7)	0.426	3(6.8)	5(16.1)	0.263
Black African	143(35.8)	104(32.0)	39(52.0)	< 0.001	26(59.1)	13(41.9)	0.143
Mixed	81(20.3)	69(21.2)	12(16.0)	0.310	4(9.1)	8(25.8)	0.063
Indian	122(30.5)	106(32.6)	16(21.3)	0.056	11(25.0)	5(16.1)	0.405
Family history of hypertension in first-degree relative n (%)	286(71.5)	229(70.5)	57(76.0)	0.338	35(79.6)	22(71.0)	0.392
Family history of premature cardiovascular disease in first-degree relative n (%)	106(26.5)	81(24.9)	25(33.3)	0.137	16(36.4)	9(29.0)	0.507
*Health behaviours*
% Adherence (MARS-5), median ± IQR	96(12)	96(12)	96(4)	< 0.001	96(4)	96(4)	0.875
Smoking status
Current smoker	52(13.0)	41(12.6)	11(14.7)	0.634	6(13.6)	5(16.1)	0.754
Past smoker	105(26.3)	91(28.0)	14(18.6)	0.098	5(11.4)	9(29.0)	0.073
Never smoker	243(60.8)	193(59.4)	50(66.7)	0.244	33(75.0)	17(54.8)	0.068
Excess alcohol consumption n (%)
Yes	80(20.0)	64(19.7)	16(21.3)	0.749	8(18.2)	8(25.8)	0.568
Dietary salt reduction n (%)
Yes	93(23.3)	76(23.4)	17(22.6)	0.397	11(25.0)	6(19.3)	0.843
Physical activity
1–3 times a week	122(30.5)	104(32.0)	18(24.0)	0.175	11(25.0)	7(22.6)	0.389
3–5 times a week	27(6.8)	22(6.8)	5(6.7)	0.975	3(6.8)	2(6.5)	0.998
> 5 times a week	2(0.5)	2(0.6)	0(0)	0.496	0(0)	0(0)	0.793
None	249(62.3)	197(60.6)	52(69.3)	0.160	30(68.2)	22(71.0)	0.362
*Anthropometric measurements*
Body mass index (BMI) kg/m², Median (IQR)	31.19 (8.2)	29.93(7.8)	32.89(10.3)	< 0.001	34.5(21.5)	30.5(6.5)	0.0386
BMI Categories, n (%)
Underweight	4(1.0)	4(1.2)	0(0)	0.334	0(0)	0(0)
Normal	67(16.8)	62(19.1)	5(6.7)	0.009	3(6.8)	2(6.5)	0.950
Overweight	118(29.5)	96(29.5)	22(29.3)	0.972	9(20.5)	13(41.9)	0.044
Obese Class I	117(29.3)	97(29.9)	20(26.7)	0.585	11(25.0)	9(29.0)	0.697
Obese Class II	56(14.0)	44(13.5)	12(16.0)	0.580	9(20.5)	3(9.7)	0.338
Obese Class III	38(9.5)	22(6.8)	16(21.3)	< 0.001	12(27.2)	4(12.9)	0.162
Waist circumference (cm), median (IQR)	99.3(18.8)	97.6(18.0)	106.5(17.4)	< 0.001	108.2(18.3)	102.4(14.7)	0.064
*Blood pressure parameters*
Systolic BP (mmHg), median (IQR)	138.0(21.7)	137.0(20.3)	146.3(25.0)	0.003	151.2(13.3)	126.7(10.6)	< 0.001
Diastolic BP (mmHg), mean (± SD)	76.1(10.4)	75.8(10.2)	77.2(11.4)	0.315	81.5(11.8)	70.9(7.2)	< 0.001
Pulse pressure mean (± SD)	61.0(19.5)	59.6(18.4)	67.3(21.7)	0.013	73.2(11.1)	55.7(9.9)	< 0.001
Blood pressure control, n (%)
Controlled	235(58.75)
Uncontrolled	165(41.25)
aTRH prevalence, n (%)	75(18.8)				44(11.0)	31(7.8)
Pseudo-resistance
Non-adherence	76(19.0)
Under-treatment	4(1.0)

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