Demographic characteristics
| CKD stages (eGFR determined by CKD-EPI equation) | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Mild-to-moderate CKD | Moderate to kidney failure | ||||||||
| Overall | No CKD | Stage 1 | Stage 2 | Stage 3a | Stage 3b | Stage 4 | Stage 5 | ||
| 2006 | 1122 | 201 | 221 | 257 | 133 | 48 | 24 | ||
| NHANES sample, n | Projected National Estimate, estimate (95% CI) | p Value* | |||||||
| Mean age, years | 60.5 (59.8 to 61.3) | 56.9 (56.0 to 57.7) | 52.9 (50.6 to 55.2) | 66.8 (65.3 to 68.3) | 70.3 (69.2 to 71.5) | 73.8 (72.6 to 75.0) | 73.2 (71.1 to 75.2) | 59.7 (58.2 to 61.3) | <0.0001 |
| Age≥65 years, % | 41.4 (39.2 to 43.7) | 28.2 (25.1 to 31.3) | 13.7 (9.4 to 18.1) | 62.7 (56.1 to 69.3) | 79.1 (73.4 to 84.8) | 87.5 (82.4 to 92.6) | 85.3 (76.7 to 94.0) | 33.3 (11.8 to 54.8) | <0.0001 |
| Gender, % male | 49.6 (46.4 to 52.8) | 49.0 (44.5 to 53.5) | 61.4 (53.8 to 68.9) | 56.0 (47.2 to 64.9) | 50.3 (40.4 to 60.2) | 38.0 (28.8 to 47.1) | 23.3 (13.6 to 33.1) | 40.6 (13.2 to 68.0) | <0.0001 |
| Mean diabetes duration†, years | 10.1 (9.5 to 10.8) | 8.7 (7.8 to 9.7) | 9.0 (7.5 to 10.4) | 13.1 (11.4 to 14.8) | 13.1 (10.9 to 15.2) | 15.8 (13.6 to 17.9) | 16.0 (13.4 to 18.6) | 8.7 (7.8 to 9.7) | <0.0001 |
| Mean eGFR (CKD-EPI), mL/min/1.73 m2 | 81.6 (80.2 to 82.9) | 92.1 (91.1 to 93.1) | 105.3 (103.2 to 107.4) | 75.8 (73.8 to 77.7) | 53.4 (52.8 to 54.0) | 38.2 (37.1 to 39.3) | 23.8 (22.5 to 25.1) | 9.0 (8.7 to 9.4) | <0.0001 |
| Mean eGFR (MDRD), mL/min/1.73 m2 | 80.3 (78.9 to 81.7) | 90.0 (88.7 to 91.3) | 108.7 (104.8 to 112.6) | 73.3 (71.5 to 75.2) | 52.7 (52.1 to 53.4) | 38.5 (37.4 to 39.6) | 24.4 (23.1 to 25.8) | 9.6 (9.2 to 10.0) | <0.0001 |
| Current smoker, % | 16.4 (14.4 to 18.4) | 17.6 (14.5 to 20.8) | 32.0 (23.6 to 40.4) | 16.3 (8.4 to 24.2) | 7.4 (3.9 to 10.8) | 3.3 (0.2 to 6.5) | 11.2 (4.1 to 18.3) | 3.0 (0.0 to 15.3) | <0.0001 |
| Race/ethnicity | |||||||||
| Non-Hispanic white, % | 60.7 (54.8 to 66.5) | 61.3 (55.1 to 67.5) | 42.4 (31.3 to 53.4) | 56.8 (46.4 to 67.2) | 69.5 (60.7 to 78.3) | 71.1 (62.6 to 79.6) | 70.6 (61.6 to 79.6) | 6.4 (4.2 to 8.5) | 0.0880 |
| Non-Hispanic black, % | 16.0 (12.0 to 20.0) | 14.9 (10.8 to 19.0) | 21.6 (14.6 to 28.7) | 14.7 (8.1 to 21.3) | 18.6 (12.8 to 24.4) | 10.9 (5.3 to 16.5) | 15.9 (8.9 to 22.8) | 63.5 (34.2 to 92.9) | 0.0969 |
| Mexican-American, % | 9.3 (5.9 to 12.6) | 8.6 (5.6 to 11.7) | 24.7 (17.1 to 32.3) | 8.8 (3.2 to 14.3) | 3.9 (1.4 to 6.4) | 6.1 (0.8 to 11.4) | 5.9 (0.0 to 12.0) | 15.1 (10.0 to 20.1) | 0.0368 |
| Other Hispanic, % | 5.8 (3.5 to 8.0) | 6.6 (4.0 to 9.1) | 5.5 (2.3 to 8.6) | 5.6 (2.4 to 8.8) | 3.5 (1.2 to 5.8) | 5.1 (2.3 to 8.0) | 0.0 (N/A) | 5.9 (0.0 to 17.8) | 0.0268 |
| Other, including multiracial, % | 8.3 (6.3 to 10.3) | 8.6 (6.4 to 10.9) | 5.9 (2.8 to 8.9) | 14.1 (6.4 to 21.8) | 4.5 (1.1 to 7.8) | 6.8 (1.0 to 12.5) | 7.6 (0.0 to 15.5) | 9.1 (0.0 to 25.3) | 0.8186 |
| Insurance status | |||||||||
| Commercial coverage, % | 56.2 (52.5 to 59.9) | 59.4 (55.1 to 63.7) | 50.2 (42.1 to 58.3) | 51.8 (41.9 to 61.7) | 54.3 (47.4 to 61.2) | 49.9 (38.3 to 61.4) | 49.8 (33.2 to 66.4) | 15.9 (0.0 to 46.3) | 0.0043 |
| Medicare, % | 19.5 (17.6 to 21.4) | 13.0 (11.1 to 15.0) | 10.0 (5.9 to 14.1) | 30.1 (22.2 to 38.0) | 32.3 (25.9 to 38.7) | 44.5 (33.4 to 55.6) | 41.8 (25.2 to 58.5) | 46.2 (23.3 to 69.1) | <0.0001 |
| Medicaid, % | 6.0 (4.6 to 7.4) | 5.7 (4.2 to 7.3) | 9.8 (4.9 to 14.7) | 6.9 (3.4 to 10.5) | 5.6 (1.8 to 9.4) | 0.3 (0.0 to 1.0) | 7.4 (3.8 to 11.0) | 17.8 (2.3 to 33.4) | 0.2587 |
| Other‡, % | 6.1 (4.3 to 8.0) | 7.4 (4.9 to 10.0) | 6.5 (2.6 to 10.3) | 4.9 (2.2 to 7.5) | 3.4 (1.9 to 4.9) | 1.8 (0.2 to 3.5) | 1.0 (0.0 to 3.2) | 12.0 (8.0 to 16.0) | 0.0097 |
| No insurance, % | 12.1 (9.9 to 14.3) | 14.4 (11.3 to 17.4) | 23.5 (17.3 to 29.8) | 6.3 (3.2 to 9.4) | 4.4 (0.6 to 8.1) | 3.5 (1.0 to 5.9) | 0.0 (N/A) | 8.1 (0.0 to 30.8) | 0.0003 |
| Comorbid conditions (self-reported) | |||||||||
| Retinopathy, % | 15.0 (13.1 to 16.9) | 10.5 (8.0 to 12.9) | 12.9 (6.5 to 19.3) | 22.8 (16.1 to 29.4) | 16.4 (11.4 to 21.4) | 26.0 (17.3 to 34.7) | 60.2 (51.4 to 68.9) | 46.2 (31.3 to 61.1) | <0.0001 |
| Congestive heart failure, % | 10.4 (8.5 to 12.3) | 5.2 (3.3 to 7.2) | 3.4 (0.9 to 6.0) | 19.5 (12.2 to 26.7) | 16.0 (9.3 to 22.6) | 29.4 (17.7 to 41.2) | 42.5 (30.6 to 54.4) | 44.0 (25.2 to 62.8) | <0.0001 |
| Coronary heart disease, % | 12.2 (10.2 to 14.3) | 8.7 (6.0 to 11.4) | 4.3 (1.5 to 7.2) | 17.3 (10.3 to 24.3) | 17.1 (11.3 to 22.9) | 28.4 (20.2 to 36.6) | 40.2 (28.0 to 52.3) | 24.6 (15.5 to 33.7) | <0.0001 |
| Angina/angina pectoris, % | 8.4 (6.7 to 10.1) | 6.9 (4.7 to 9.0) | 4.2 (0.4 to 8.0) | 9.3 (5.1 to 13.6) | 10.3 (5.7 to 14.8) | 17.1 (8.4 to 25.9) | 23.8 (7.0 to 40.6) | 19.2 (0.0 to 45.7) | 0.0082 |
| Myocardial infarction, % | 11.0 (9.2 to 12.8) | 8.2 (5.9 to 10.4) | 6.9 (3.4 to 10.5) | 12.6 (7.4 to 17.7) | 18.3 (11.1 to 25.6) | 17.7 (11.1 to 24.3) | 33.6 (15.3 to 51.9) | 24.6 (15.5 to 33.7) | <0.0001 |
| Stroke, % | 8.8 (7.2 to 10.4) | 4.7 (3.2 to 6.1) | 6.8 (2.3 to 11.2) | 15.9 (8.9 to 22.9) | 14.6 (9.9 to 19.4) | 22.8 (15.9 to 29.6) | 25.6 (13.8 to 37.4) | 18.7 (0.0 to 38.7) | <0.0001 |
| Hypertension§, % | 77.6 (74.7 to 80.5) | 70.9 (66.7 to 75.0) | 73.5 (64.7 to 82.3) | 90.7 (86.4 to 95.0) | 90.7 (86.1 to 95.3) | 94.0 (88.8 to 99.1) | 96.8 (91.4 to 100.0) | 97.9 (97.2 to 98.6) | <0.0001 |
| Vital signs | |||||||||
| Mean SBP, mm Hg | 129.7 (128.6 to 130.8) | 125.9 (124.4 to 127.3) | 132.9 (129.7 to 136.2) | 138.5 (135.1 to 142.0) | 133.0 (130.0 to 136.1) | 136.3 (131.6 to 141.1) | 140.3 (133.4 to 147.3) | 144.5 (127.3 to 161.7) | <0.0001 |
| Mean DBP, mm Hg | 68.6 (67.7 to 69.5) | 70.1 (69.1 to 71.0) | 75.0 (72.4 to 77.6) | 67.9 (65.0 to 70.9) | 62.5 (60.2 to 64.8) | 61.8 (59.3 to 64.2) | 60.4 (57.5 to 63.3) | 64.2 (59.2 to 69.2) | <0.0001 |
| BMI | 33.2 (32.7 to 33.7) | 33.3 (32.6 to 34.0) | 33.4 (32.1 to 34.7) | 32.3 (31.1 to 33.6) | 33.7 (32.5 to 34.9) | 33.6 (31.9 to 35.3) | 30.6 (29.1 to 32.0) | 31.0 (29.0 to 33.0) | 0.4885 |
| <25, % | 11.8 (9.6 to 14.1) | 10.5 (7.7 to 13.2) | 15.3 (8.7 to 21.9) | 17.2 (10.2 to 24.1) | 11.8 (7.2 to 16.4) | 12.9 (6.5 to 19.2) | 8.3 (1.6 to 15.0) | 21.6 (4.6 to 38.7) | 0.1691 |
| 25–29.9, % | 23.7 (21.2 to 26.3) | 25.9 (22.5 to 29.3) | 18.7 (13.5 to 23.8) | 20.0 (14.8 to 25.2) | 17.7 (12.1 to 23.2) | 21.9 (13.9 to 30.0) | 40.0 (22.6 to 57.4) | 12.2 (9.7 to 14.7) | 0.0025 |
| ≥30, % | 64.4 (60.9 to 68.0) | 63.7 (59.1 to 68.2) | 66.0 (58.1 to 73.9) | 62.9 (55.3 to 70.4) | 70.5 (63.8 to 77.2) | 65.2 (57.4 to 73.0) | 51.7 (34.3 to 69.1) | 66.2 (51.1 to 81.2) | 0.2726 |
| Blood tests | |||||||||
| Mean creatinine, mg/dL | 1.0 (1.0 to 1.0) | 0.8 (0.8 to 0.8) | 0.7 (0.7 to 0.8) | 1.0 (0.9 to 1.0) | 1.2 (1.2 to 1.3) | 1.5 (1.5 to 1.6) | 2.2 (2.1 to 2.4) | 6.2 (5.9 to 6.5) | <0.0001 |
| Mean uric acid, mg/dL | 5.9 (5.8 to 6.0) | 5.5 (5.4 to 5.7) | 5.5 (5.2 to 5.7) | 6.1 (5.8 to 6.4) | 6.6 (6.3 to 6.9) | 7.3 (7.0 to 7.7) | 8.0 (7.4 to 8.7) | 6.0 (5.5 to 6.5) | <0.0001 |
| Mean HDL, mg/dL | 46.4 (45.6 to 47.1) | 46.4 (45.3 to 47.6) | 45.4 (43.6 to 47.2) | 46.4 (43.6 to 49.2) | 46.4 (44.5 to 48.3) | 46.8 (44.2 to 49.4) | 47.0 (43.2 to 50.8) | 43.6 (38.5 to 48.7) | 0.8612 |
| Mean UACR, mg/g | 137.1 (101.7 to 172.5) | 10.3 (9.8 to 10.8) | 163.2 (120.9 to 205.4) | 369.1 (222.1 to 516.1) | 239.8 (58.1 to 421.6) | 348.5 (104.7 to 592.3) | 575.7 (332.6 to 818.7) | N/A¶ | <0.0001 |
| Mean HbA1c, % | 7.2 (7.1 to 7.3) | 7.1 (7.0 to 7.2) | 8.1 (7.8 to 8.5) | 7.6 (7.3 to 7.8) | 7.0 (6.8 to 7.2) | 7.1 (6.8 to 7.4) | 7.0 (6.6 to 7.4) | 7.3 (6.8 to 7.8) | <0.0001 |
| HbA1c <7%, % | 55.6 (50.1 to 61.1) | 58.4 (51.7 to 65.1) | 38.3 (22.5 to 54.2) | 44.9 (32.0 to 57.8) | 61.1 (46.5 to 75.7) | 57.7 (42.1 to 73.4) | 55.0 (29.0 to 81.1) | 70.2 (32.3 to 100.0) | 0.0307 |
| HbA1c 7%–<8%, % | 21.0 (18.3 to 23.7) | 19.6 (16.2 to 23.0) | 16.8 (10.3 to 23.3) | 27.9 (18.6 to 37.1) | 20.8 (14.3 to 27.3) | 28.2 (19.1 to 37.3) | 29.9 (17.8 to 42.0) | 2.4 (1.6 to 3.3) | 0.2741 |
| HbA1c≥8%, % | 23.4 (19.4 to 27.4) | 22.0 (16.6 to 27.4) | 44.9 (31.3 to 58.5) | 27.2 (16.9 to 37.6) | 18.1 (8.6 to 27.6) | 14.1 (5.4 to 22.7) | 15.1 (0.7 to 32.7) | 27.4 (11.2 to 50.6) | 0.0122 |
*Statistical testing was performed to compare patients with no CKD, mild-to-moderate CKD, and moderate CKD to kidney failure. ANOVA t test was used for continuous variable. Wald χ2 test was used for categorical variable. p Value cannot be calculated if any of the table cell contains 0 expected frequency.
†Mean diabetes duration was only calculated within respondents with self-reported age≤79 years at the time of the survey and non-missing self-reported age≤79 years when first diagnosed with diabetes.
‡Other insurance includes Medi-Gap, State Children's Health Insurance Program (SCHIP), military healthcare, state-sponsored health plan, other government insurance, and single service plan.
§In addition to self-reported hypertension, respondents with measured mean systolic blood pressure/diastolic blood pressure>140/90 mm Hg and/or self-reported use of antihypertensive agents were identified as patients with hypertension.
¶Unable to estimate due to small sample size and missing data.
BMI, body mass index; CKD, chronic kidney disease; CKD-EPI, the Chronic Kidney Disease Epidemiology Collaboration equation; DBP, diastolic blood pressure; eGFR, estimated glomerular filtration rate; HbA1C, hemoglobin A1c; HDL, high-density lipoprotein; MDRD, Modification of Diet in Renal Disease Study equation; SBP, systolic blood pressure; UACR, urinary albumin:creatinine ratio.