Table 1

Baseline demographic and other variables: a randomised controlled potassium diet intervention study in patients suffering from rheumatoid arthritis (RA) and on standard care (A: potassium-rich diet; B: potassium-rich diet plus potassium food supplement; C: routine diet)

Age, mean (years)50.5 (11.2)47.3 (12.1)46.9 (10.5)0.40*
Women (per cent)8591920.70**
Duration (years) RA, mean, median10.6 (8.1), 88.5 (7.4),67.4 (5.9), 50.08*
Body mass index, mean (Kg/m2)24.4 (3.8)24.3 (4.3)24.2 (2.9)0.90*
Pain Score (VAS)>5 cms (per cent)52.654.4500.87**
Erosion hand/joint deformity (per cent)75.450.862.10.15**
Prior continuous DMARD use duration (month), median (range)26 (6–240)18 (6–360)21(6-216)0.47*
ESR mm fall first hour, mean70.6 (2.2)68.8 (3.7)67.4 (3.9)0.84*
C-reactive protein mg/dL, mean33.3 (39.4)26.2 (31.1)25.5 (37.8)0.45*
RF seropositive (per cent)7683680.07**
Serum potassium mEq/L, mean3.9 (0.5)3.8 (0.6)3.9 (0.5)0.59*
Urine potassium mEq/L, mean44.4 (25.6)46.7 (25.8)42.9 (29.1)0.88*
DMARD single or combination plus Pred use (per cent)70.261.470.60.49**
DMARD single agent only (per cent)19.322.8190.89**
Methotrexate use (per cent)82.487.8600.00**
Sulfasalazine use (per cent)3319470.01**
Hydroxychloroquine use (per cent)4040470.27**
Analgesic use† (per cent)8195900.07**
Daily Pred dose mg, mean5.4 (2.8)5.3 (2.5)5.5 (2.3)0.94*
Weekly methotrexate dose mg, mean14.8 (4.4)14.9 (4.4)13.9 (4.3)0.56*
Blood Haemoglobin g/dL, mean11.6 (1.3)11.6 (1.3)12.1 (1.3)0.07*
  • †Analgesic includes paracetamol and other analgesic use of non-steroidal anti-inflammatory drug/NSAID (diclofenac, naprosyn, etorocoxib, etodolac, nimesulide) more than 4 times a week.

  • *Analysis of variance.

  • **χ2 statistic using count.

  • */**significance: p<0.05, two-tailed.

  • Per cent pertains to proportion of subjects positive.

  • Mono: single drug; standard deviation shown in parenthesis after mean; see text for details.

  • DMARD, disease-modifying antirheumatic drug (methotrexate, sulfasalazine, hydroxychloroquine); n, number of patients; Pred, prednisolone.