Table 2: Baseline characteristics for African-American and white treatment resistant hypertension cases and controls.

CharacteristicAfrican-American participantsWhite participants
TRH casesControls value*TRH casesControls value*

Sample size, 92971912741635
Age (y), mean (SD)65.8 (7.1)65.7 (7.4) 0.9267.4 (7.2)66.6 (7.5)0.003
Women, (%) 440 (47.4)391 (54.4)0.005440 (34.5)712 (43.6)<0.001
On antihypertensive treatment at baseline, (%)892 (96.0)618 (86.0)<0.0011221 (95.8)1448 (88.6)<0.001
Randomized treatment group:
 Chlorthalidone**, (col%)253 (27.2)366 (50.9)<0.001420 (33.0)695 (42.5)<0.001
 Amlodipine, (col%)166 (17.9)161 (22.4)236 (18.5)349 (21.4)
 Lisinopril, (col%)301 (32.4)118 (16.4)383 (30.1)429 (26.2)
 Doxazosin, (col%)209 (22.5)74 (10.3)235 (18.5)162 (9.9)
Baseline blood pressure:
 All participants, mm Hg:
  SBP, mean (SD)151.9 (15.6)138.9 (15.5)<0.001152.3 (14.9)139.2 (15.4)<0.001
  DBP, mean (SD)85.2 (11.1)83.2 (9.3)<0.00183.1 (10.5)82.5 (9.5)0.09
 Treated at baseline, mm Hg:
  SBP, mean (SD)151.5 (15.6)136.6 (14.9)<0.001151.9 (14.8)137.6 (15.0)<0.001
  DBP, mean (SD)85.0 (11.1)82.2 (9.2)<0.00183.0 (10.4)81.8 (9.5)0.002
 Untreated at baseline, mm Hg:
  SBP, mean (SD)162.7 (13.3)153.4 (10.9)<0.001162.3 (12.7)152.1 (11.1)<0.001
  DBP, mean (SD)89.6 (11.1)88.9 (8.3)0.6985.6 (11.5)87.6 (7.9)0.14
Current cigarette smoker, (%)185 (19.9)200 (27.8)<0.001243 (19.1)336 (20.6)0.32
Type 2 diabetes, (%)435 (46.8)227 (31.6)<0.001531 (41.7)458 (28.0)<0.001
LVH by electrocardiogram, (%)273 (29.4)149 (20.7)<0.001178 (14.0)212 (13.0)0.43
Body mass index, mean (SD), kg/m231.3 (8.3)29.5 (6.4)<0.00129.9 (5.7)28.9 (5.3)<0.001
Fasting glucose, mean (SD), mg/dL132.8 (62.5)120.4 (60.8)<0.001124.8 (50.8)114.8 (48.1)<0.001
Total cholesterol, mean (SD), mg/dL217.1 (45.4)216.0 (44.7)0.64213.6 (43.9)215.0 (41.7)0.38
HDL cholesterol, mean (SD), mg/dL 50.6 (15.9)52.8 (15.8)0.00842.9 (13.7)45.1 (14.0)<0.001
Fasting triglycerides, mean (SD), mg/dL130.0 (75.9)125.4 (91.9)0.33196.8 (142.9)177.7 (126.0)<0.001
Estimated glomerular filtration rate (eGFR)80.3 (21.3)86.2 (19.6)<0.00173.9 (18.3)75.8 (16.5)0.004
Follow-up blood pressure, mm Hg:
 SBP at 1 year, mean (SD)151.4 (18.4)129.1 (13.5)<0.001147.2 (17.7)128.1 (12.2)<0.001
 DBP at 1 year, mean (SD)83.8 (11.3)78.1 (8.5)<0.00179.0 (10.4)76.5 (8.6)<0.001
 SBP at 2 years, mean (SD)149.6 (18.8)127.9 (13.0)<0.001146.4 (17.2)126.3 (11.9)<0.001
 DBP at 2 years, mean (SD)81.4 (12.5)77.1 (8.6)<0.00178.0 (10.8)75.5 (7.9)<0.001
 SBP at 3 years, mean (SD)152.3 (18.3)117.2 (6.5)<0.001149.2 (16.9)117.9 (6.3)<0.001
 DBP at 3 years, mean (SD)81.1 (12.3)73.1 (6.9)<0.00177.2 (11.6)72.0 (7.2)<0.001
 Number of HT meds at 3 years, mean (SD)3.6 (0.72)1 (per def.)3.6 (0.69)1 (per def.)
 Number on diuretic at 3 years, (%)493 (53%)366 (51%)0.38769 (60%)695 (43%)<0.001

SBP: systolic blood pressure, DBP: diastolic blood pressure, HDL-C: HDL cholesterol, and LVH: left ventricular hypertrophy.
*Test of differences between case/control groups: ANOVA for continuous variables and chi-square for categorical variables.
**Participants were randomized to treatment in a ratio of 1 : 1 : 1 : 1.7 for amlodipine, lisinopril, doxazosin, and chlorthalidone, respectively.