Table 1.

Characteristics of patients at baseline

CharacteristicsSPS (n=16)Placebo (n=17)
Sex, no. (%)
 Men10 (62.5)13 (76.5)
Age, yr72.7 (±11.6)71.9 (±9.6)
Serum creatinine, mg/dla3.0 (±0.8)3.6 (±1.3)
eGFR (MDRD), ml/min per 1.73 m220.0 (±7.2)17.7 (±6.6)
CKD stage, no. (%)
 3 (30–59 ml/min per 1.73 m2)2 (12.5)1 (5.9)
 4 (15–29 ml/min per 1.73 m2)10 (62.5)9 (52.9)
 5 (<15 ml/min per 1.73 m2)4 (25.0)7 (41.2)
Cause of CKD, no. (%)
 Vascular (includes diabetic nephropathy)14 (87.5)12 (70.6)
 GN02 (11.8)
 Polycystic1 (6.3)0
 Other1 (6.3)3 (17.6)
Body mass index, kg/m227.4 (±6.4)29.4 (±6.0)
Comorbidities, no. (%)
 Dyslipidemia13 (81.3)16 (94.1)
 Hypertension14 (87.5)15 (88.2)
 Diabetes11 (68.8)13 (76.5)
 Coronary artery disease8 (50.0)11 (64.7)
 History of stroke1 (6.3)4 (23.5)
 Arrhythmia01 (5.9)
 Congestive heart failure3 (18.8)0
Medication, no. (%)
 Any medication affecting potassium15 (93.8)16 (94.1)
 Insulin4 (25.0)10 (58.8)
β-Blockers12 (75.0)9 (52.9)
 Loop diuretics10 (62.5)8 (47.1)
 ACEIs or ARBsb13 (81.3)10 (58.8)
 Thiazide diuretics2 (12.5)2 (11.8)
 Potassium-sparing diuretics02 (11.8)
 Laxatives2 (12.5)2 (11.8)
 NSAIDsc00
BP, mmHg
 Systolic150.0 (±21.3)141.9 (±13.4)
 Diastolic69.1 (±8.1)68.1 (±8.8)
Use of SPS immediately before study enrolment, no. (%)4 (25.0)5 (29.4)
  • SPS, sodium polystyrene sulfonate; MDRD, Modification of Diet in Renal Disease four–variable equation; ACEI, angiotensin–converting enzyme inhibitor; ARB, angiotensin receptor blocker; NSAID, nonsteroidal anti–inflammatory drug.

  • a To convert creatinine levels from milligrams per deciliter to millimoles per liter, multiply by 88.4.

  • b No patient was using an ACEI combined with an ARB.

  • c Excludes aspirin at 80 mg daily.