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Table 1 Characteristics at diagnosis of patients with incident gout between 2006 and 2009

From: Incident gout and chronic Kidney Disease: healthcare utilization and survival

  All gout patients Gout patients without CKD Gout patients with CKD p-valuec
Total 12,940 8286 4654  
Died during follow-up, n (%) 3421 (26.4%) 1110 (13.4%) 2311 (49.7%) < 0.001
Person-years 57,206 39,014 18,192  
Age (years)
 Mean ± SD 63.8 ± 15.6 58.1 ± 14.7 74.0 ± 11.3 < 0.001
 IQR 25–75 53–76 48–69 68–82  
Age, n (%)     < 0.001
 25–34 years 621 (4.8%) 590 (7.1%) 31 (0.7%)  
 35–44 years 992 (7.7%) 940 (11.3%) 52 (1.1%)  
 45–54 years 1924 (14.9%) 1740 (21.0%) 184 (4.0%)  
 55–64 years 2799 (21.6%) 2210 (26.7%) 589 (12.7%)  
 65–74 years 2917 (22.5%) 1637 (19.8%) 1280 (27.5%)  
 75–84 years 2739 (21.2%) 946 (11.4%) 1793 (38.5%)  
 85+ years 948 (7.3%) 223 (2.7%) 725 (15.6%)  
Sex, n (%)     < 0.001
 Male 9819 (75.9%) 6634 (80.1%) 3185 (68.4%)  
 Female 3121 (24.1%) 1652 (19.9%) 1469 (31.6%)  
Socio-economic status, n (%)     < 0.001
 Low 2495 (19.3%) 1728 (20.9%) 767 (16.5%)  
 Medium 5717 (44.2%) 3582 (43.2%) 2135 (45.9%)  
 High 4651 (35.9%) 2913 (35.1%) 1738 (37.3%)  
 Missing 77 (0.6%) 63 (0.8%) 14 (0.3%)  
Smoking habits, n (%)     < 0.001
 Never smoker 7652 (59.1%) 4818 (58.2%) 2834 (60.9%)  
 Former smoker 3346 (25.9%) 2025 (24.4%) 1321 (28.4%)  
 Current 1628 (12.6%) 1313 (15.8%) 315 (6.8%)  
 Missing 314 (2.4%) 130 (1.6%) 184 (4.0%)  
BMI (kg/m2), n (%)     < 0.001
 Underweight 60 (0.5%) 35 (0.4%) 25 (0.5%)  
 Normal 2013 (15.6%) 1095 (13.2%) 918 (19.7%)  
 Overweight 4794 (37.0%) 3097 (37.4%) 1697 (36.5%)  
 Obese 5559 (43.0%) 3755 (45.3%) 1804 (38.8%)  
 Missing 514 (4.0%) 304 (3.7%) 210 (4.5%)  
Comorbid condition at index date, n (%)
 CVD 4968 (38.4%) 2070 (25.0%) 2898 (62.3%) < 0.001
 Diabetes 3743 (28.9%) 1883 (22.7%) 1860 (40.0%) < 0.001
 Hypertension 8494 (65.6%) 4367 (52.7%) 4127 (88.7%) < 0.001
 Cancer 1571 (12.1%) 696 (8.4%) 875 (18.8%) < 0.001
CCI
 Mean ± SD 2.1 ± 2.3 1.2 ± 1.5 3.6 ± 2.7 < 0.001
 IQR 25–75 0–3 0–2 2–5  
CCI, n (%)     < 0.001
 0 3987 (30.9%) 3473 (42.0%) 513 (11.0%)  
 1 2985 (23.1%) 2376 (28.7%) 609 (13.1%)  
 2 1853 (14.3%) 1168 (14.1%) 685 (14.7%)  
 3 1300 (10.1%) 602 (7.3%) 698 (15.0%)  
 4 906 (7.0%) 305 (3.7%) 601 (12.9%)  
 5 648 (5.0%) 174 (2.1%) 474 (10.2%)  
 6 477 (3.7%) 94 (1.1%) 383 (8.2%)  
 7+ 767 (5.9%) 78 (0.9%) 689 (14.8%)  
 Missing 17 (0.1%) 16 (0.2%) 2 (0.0%)  
sUA levels (mg/dL)
 Mean ± SD 8.1 ± 2.0 7.6 ± 1.7 8.9 ± 2.1 < 0.001
 IQR25–75 6.8–9.3 6.4–8.7 7.5–10.1  
sUA levels (mg/dL)     < 0.001
  ≤ 6 1343 (10.4%) 981 (11.8%) 362 (7.8%)  
  > 6 7796 (60.2%) 4175 (50.4%) 3621 (77.8%)  
 Missing 3801 (29.4%) 3130 (37.8%) 671 (14.4%)  
Gout medicationb, n (%) 4068 (31.4%) 2245 (27.1%) 1823 (39.2%) < 0.001
  1. Note: BMI = body mass index; BP = blood pressure; CCI=Charlson Comorbidity Index: CKD = chronic kidney disease; CVD = cardiovascular disease; IQR = interquartile range; SD = standard deviation; sUA = serum uric acid
  2. aValues for most clinical characteristics at index date are the last value in the year prior to index date. In cases where this value is missing the following were used: smoking – closest record to index date through follow-up; BMI – closest record to index date for up to 3 years follow-up; systolic BP, diastolic BP, glucose, and creatinine – closest record to index date for up to 1 year follow-up. sUA levels were the lowest level during the 12 months prior to index date. Patients were considered positive for CVD, diabetes or hypertension if they ever received a diagnosis prior to index date, and positive for diuretic use if they purchased a diuretic in the year prior to index date. The CCI was the value at index date, 17 cases had missing values
  3. bGout medication is defined as any purchase of at least one of the following medications prior to index date: allopurinol, febuxostat, probenecid, sulfinpyrazone, or colchicine
  4. cThe chi square test, ANOVA or t-test were used to assess differences in distribution between the CKD groups