Background
Methods
Study design and sample
Definition of Outcomes
Predictor variables
-
Age at study entry (in single years)
-
Body mass index
-
Systolic blood pressure (mmHg)
-
Smoking status (non-smoker, ex-smoker; light smoker: < 10 cigarettes/day, moderate smoker: 10-19 cigarettes per day, heavy smoker: 20 or more cigarettes per day)
-
Ethnic group
-
Townsend deprivation score (derived from the patient's postcode) [20]
-
Diagnosis of type 1 diabetes
-
Diagnosis of type 2 diabetes
-
Diagnosis of cardiovascular disease
-
Diagnosis of rheumatoid arthritis
-
Treated hypertension
-
Diagnosis of congestive cardiac failure
-
Diagnosis of peripheral vascular disease
-
Diagnosis of systemic lupus erythematosis
-
Two or more prescriptions for NSAIDs drugs in the 6 months before study entry
-
Evidence of kidney stones based on diagnosis or operative procedure at baseline
-
Recorded family history of kidney disease including polycystic kidneys
-
Prostatic hypertrophy at baseline (men)
Statistical analysis
Results
Study population
QResearch
derivation cohort
(n = 1,574,749)
|
THIN
Validation cohort
(n = 1,581,745)
| |
---|---|---|
Women | 775,091 (49.22) | 784005 (49.57) |
Mean age(SD) | 47.3 (11.1) | 49 (11.1) |
Mean Townsend deprivation score (SD) | -0.5 (3.4) | -0.7 (3.1) |
Ethnic group
| ||
white/not recorded | 1,511,028 (95.95) | 1,548,749 (97.91) |
Indian | 12,360 (0.78) | 8,313 (0.53) |
Pakistani | 6,582 (0.42) | 2,370 (0.15) |
Bangladeshi | 2,671 (0.17) | 797 (0.05) |
Other Asian | 5,239 (0.33) | 3,652 (0.23) |
Black Caribbean | 9,596 (0.61) | 4,131 (0.26) |
Black African | 10,535 (0.67) | 5,224 (0.33) |
Chinese | 2,819 (0.18) | 1,279 (0.08) |
Other | 13,919 (0.88) | 7,230 (0.46) |
Smoking status
| ||
non smoker | 804,831 (51.11) | 641,929 (40.58) |
ex smoker | 286,731 (18.21) | 236,820 (14.97) |
light smoker | 101,273 (6.43) | 96,347 (6.09) |
moderate smoker | 124,246 (7.89) | 153,262 (9.69) |
heavy smoker | 100,891 (6.41) | 150,036 (9.49) |
smoker amount not recorded | 42,309 (2.69) | 204,564 (12.93) |
smoking not recorded | 114,468 (7.27) | 98,787 (6.25) |
Clinical conditions
| ||
Type 1 diabetes | 4,441 (0.28) | 4,940 (0.31) |
Type 2 diabetes | 49,179 (3.12) | 49,877 (3.15) |
Cardiovascular disease | 70,865 (4.50) | 80,977 (5.12) |
Congestive cardiac failure | 7,366 (0.47) | 8,073 (0.51) |
Peripheral vascular disease | 16,015 (1.02) | 20,066 (1.27) |
Treated hypertension | 156,506 (9.94) | 142,192 (8.99) |
Rheumatoid arthritis | 11,933 (0.76) | 14,137 (0.89) |
Systemic lupus erythematosis | 1,094 (0.07) | 1,103 (0.07) |
Kidney Stones | 10,674 (0.68) | 12,115 (0.77) |
Current use of NSAIDS | 425,775 (27.04) | 387,087 (24.47) |
Family history of kidney disease | 719 (0.05) | 1,097 (0.07) |
Clinical values
| ||
systolic blood pressure recorded | 1,415,467 (89.89) | 1,437,893 (90.91) |
mean systolic blood pressure (SD) | 133.1 (19.5) | 133.6 (19.6) |
body mass index recorded | 1,241,158 (78.82) | 1,253,686 (79.26) |
mean body mass index (SD) | 26.7 (4.7) | 26.8 (4.7) |
creatinine recorded ever | 880,627 (55.92) | 863,948 (54.62) |
mean Creatinine (SD) | 86.2 (15.9) | 86.3 (16.3) |
creatinine recorded prior to baseline | 331,018 (21.02) | 217,814 (13.77) |
complete data (for SBP, BMI & smoking) | 1,214,906 (77.15) | 1,226,974 (77.57) |
Missing data
Incidence rates for both outcomes
QResearch
derivation cohort
|
THIN
validation cohort
| ||
---|---|---|---|
Women
|
Total
|
58.46 (57.72 to 59.21)
|
64.61 (63.81 to 65.43)
|
35-39 yrs
| 5.27 (4.76 to 5.83) | 5.57 (5.02 to 6.17) | |
40-44 yrs
| 7.11 (6.49 to 7.79) | 9.34 (8.59 to 10.15) | |
45-49 yrs
| 14.09 (13.13 to 15.11) | 14.62 (13.62 to 15.70) | |
50-54 yrs
| 24.35 (23.07 to 25.70) | 26.61 (25.23 to 28.07) | |
55-59 yrs
| 43.76 (42.02 to 45.56) | 47.98 (46.11 to 49.93) | |
60-64 yrs | 89.55 (86.70 to 92.50) | 99.94 (96.83 to 103.14) | |
65-69 yrs
| 167.61 (163.41 to 171.92) | 182.76 (178.22 to 187.43) | |
70-74 yrs
| 291.44 (285.44 to 297.57) | 315.58 (309.13 to 322.16) | |
Men
|
Total
|
42.05 (41.43 to 42.68)
|
49.81 (49.10 to 50.52)
|
35-39 yrs
| 4.61 (4.15 to 5.12) | 6.26 (5.69 to 6.89) | |
40-44 yrs
| 6.82 (6.23 to 7.47) | 9.92 (9.17 to 10.74) | |
45-49 yrs
| 11.7 (10.85 to 12.61) | 15.72 (14.70 to 16.82) | |
50-54 yrs
| 18.82 (17.71 to 19.99) | 24.06 (22.76 to 25.44) | |
55-59 yrs
| 33.47 (31.96 to 35.04) | 40.93 (39.21 to 42.73) | |
60-64 yrs
| 65.64 (63.19 to 68.19) | 75.49 (72.77 to 78.31) | |
65-69 yrs
| 129.01 (125.23 to 132.90) | 150.21 (145.98 to 154.56) | |
70-74 yrs
| 224.47 (218.85 to 230.24) | 248.59 (242.41 to 254.93) |
QResearch
derivation cohort
|
THIN
validation cohort
| ||
---|---|---|---|
Women
|
total
|
3.03 (2.87 to 3.20)
|
3.03 (2.86 to 3.21)
|
35-39 yrs
| 0.83 (0.65 to 1.07) | 0.70 (0.52 to 0.93) | |
40-44 yrs
| 0.95 (0.74 to 1.22) | 1.18 (0.93 to 1.49) | |
45-49 yrs
| 1.40 (1.12 to 1.74) | 1.41 (1.13 to 1.78) | |
50-54 yrs
| 1.64 (1.33 to 2.02) | 1.95 (1.61 to 2.38) | |
55-59 yrs
| 2.56 (2.17 to 3.02) | 2.99 (2.55 to 3.50) | |
60-64 yrs
| 4.45 (3.86 to 5.13) | 4.29 (3.69 to 4.98) | |
65-69 yrs
| 6.44 (5.68 to 7.30) | 7.00 (6.18 to 7.93) | |
70-74 yrs
| 11.6 (10.52 to 12.79) | 9.59 (8.58 to 10.72) | |
Men
|
Total
|
3.66 (3.48 to 3.85)
|
3.88 (3.69 to 4.08)
|
35-39 yrs
| 1.01 (0.80 to 1.26) | 1.19 (0.95 to 1.48) | |
40-44 yrs
| 1.18 (0.95 to 1.47) | 1.55 (1.27 to 1.89) | |
45-49 yrs
| 1.51 (1.22 to 1.86) | 1.98 (1.64 to 2.39) | |
50-54 yrs
| 2.30 (1.94 to 2.73) | 2.38 (2.00 to 2.84) | |
55-59 yrs
| 3.64 (3.17 to 4.18) | 3.58 (3.10 to 4.14) | |
60-64 yrs
| 5.09 (4.44 to 5.82) | 5.22 (4.55 to 5.99) | |
65-69 yrs
| 9.48 (8.52 to 10.55) | 9.71 (8.70 to 10.83) | |
70-74 yrs
| 14.24 (12.93 to 15.68) | 14.36 (12.98 to 15.88) |
Model Development
Moderate-severe CKD
Adjusted hazard ratio
(95%CI)
women
|
Adjusted hazard ratio
(95%CI)
men
| |
---|---|---|
Ethnic group
| ||
White or ethnicity not recorded | ||
Indian§
| 1.03 (.896 to 1.18) | 1.16 (1.01 to 1.34) |
Pakistani§
| 1.55 (1.32 to 1.81) | 2.00 (1.70 to 2.35) |
Bangladeshi§
| 1.50 (1.14 to 1.95) | 1.35 (1.03 to 1.78) |
Other Asian§
| 1.16 (0.89 to 1.52) | 1.44 (1.09 to 1.90) |
Black Caribbean§
| 0.48 (0.41 to 0.57) | 0.83 (0.69 to 0.99) |
Black African§
| 0.56 (0.43 to 0.74) | 1.17 (0.90 to 1.54) |
Chinese§
| 1.13 (0.77 to 1.65) | 1.36 (0.89 to 2.07) |
Other ethnic group§
| 1.23 (1.07 to 1.40) | 1.33 (1.13 to 1.57) |
Co-morbidity
| ||
Type 1 diabetes ±
| 8.21 (6.74 to 9.99) | 12.3 (10.3 to 14.6) |
Type 2 diabetes ±
| 4.50 (4.14 to 4.89) | 6.07 (5.61 to 6.57) |
Cardiovascular disease ±
| 1.37 (1.32 to 1.42) | 1.40 (1.34 to 1.45) |
Congestive cardiac failure ±
| 2.27 (2.11 to 2.45) | 2.84 (2.66 to 3.03) |
Peripheral vascular disease | 1.35 (1.25 to 1.46) | 1.47 (1.37 to 1.57) |
Treated hypertension ±
| 2.49 (2.33 to 2.66) | 2.78 (2.59 to 2.99) |
NSAID use ±
| 1.30 (1.27 to 1.34) | 1.29 (1.25 to 1.33) |
Family history of kidney disease ±
| 2.13 (1.39 to 3.27) | 3.58 (2.19 to 5.84) |
Rheumatoid arthritis ±
| 1.62 (1.51 to 1.75) | 1.48 (1.30 to 1.67) |
Systemic lupus erythematosis ±
| 2.40 (1.92 to 3.00) | n/a* |
History of kidney stones ±
| 1.27 (1.11 to 1.46) | n/a* |
Smoking status
| ||
Non smoker | 1.00 | 1.00 |
Ex smoker ±
| 1.19 (1.15 to 1.23) | 1.13 (1.09 to 1.17) |
Light smoker ±
| 1.30 (1.23 to 1.38) | 1.15 (1.08 to 1.22) |
Moderate smoker ±
| 1.27 (1.21 to 1.34) | 1.24 (1.16 to 1.32) |
Heavy smoker ±
| 1.43 (1.34 to 1.52) | 1.25 (1.16 to 1.34) |
Townsend score (per 5 unit increase) | 1.16 (1.14 to 1.18) | 1.10 (1.08 to 1.19) |
End Stage Kidney Failure
Adjusted hazard ratio
(95%CI)
women
|
Adjusted hazard ratio
(95%CI)
men
| |
---|---|---|
Ethnic group
| ||
White or ethnicity not recorded | ||
Indian§
| 1.16 (.691 to 1.94) | 1.37 (0.90 to 2.07) |
Pakistani§
| 2.48 (1.54 to 3.98) | 1.83 (1.05 to 3.18) |
Bangladeshi§
| 0.93 (0.30 to 2.90) | 1.22 (0.54 to 2.75) |
Other Asian§
| 3.07 (1.64 to 5.76) | 2.39 (1.19 to 4.81) |
Black Caribbean§
| 1.01 (0.64 to 1.61) | 1.56 (1.01 to 2.43) |
Black African§
| 1.63 (0.89 to 2.99) | 1.87 (0.99 to 3.51) |
Chinese§
| 3.50 (1.56 to 7.84) | insufficient numbers |
Other ethnic group§
| 1.36 (0.82 to 2.23) | 0.96 (0.52 to 1.79) |
Co-morbidity
| ||
Type 1 diabetes ±
| 22.3 (14.7 to 33.8) | 11.3 (7.59 to 16.9) |
Type 2 diabetes ±
| 4.68 (3.58 to 6.11) | 2.79 (2.17 to 3.58) |
Cardiovascular disease ±
| 1.35 (1.14 to 1.58) | 1.34 (1.18 to 1.53) |
Congestive cardiac failure ±
| 4.45 (3.55 to 5.57) | 4.02 (3.33 to 4.86) |
Peripheral vascular disease | 1.7 (1.3 to 2.23) | 1.98 (1.62 to 2.42) |
Treated hypertension ±
| 4.8 (3.96 to 5.82) | 6.77 (5.71 to 8.02) |
Family history of kidney disease ±
| 6.41 (2.4 to 17.1) | 9.68 (4.01 to 23.4) |
Rheumatoid arthritis ±
| 1.52 (1.1 to 2.1) | 1.53 (1.01 to 2.34) |
Systemic lupus erythematosis ±
| 4.69 (2.63 to 8.35) | n/a |
History of kidney stones ±
| 2.07 (1.34 to 3.19) | n/a |
Smoking status
| ||
Non smoker | ||
Ex smoker ±
| 1.22 (1.06 to 1.40) | 1.16 (1.03 to 1.3) |
Light smoker ±
| 1.45 (1.13 to 1.85) | 1.17 (0.98 to 1.41) |
Moderate smoker ±
| 1.08 (0.85 to 1.38) | 1.33 (1.09 to 1.63) |
Heavy smoker ±
| 1.43 (1.11 to 1.83) | 1.09 (.858 to 1.38) |
Townsend score (per 5 unit increase) | 1.23 (1.13 to 1.34) | 1.10 (1.02 to 1.19) |
Validation of the risk prediction algorithms
moderate-severe CKD
|
End Stage Kidney Failure
| ||
---|---|---|---|
Women | THIN cohort | ||
R2 statistic (%) | 56.19 (55.67 to 56.70) | 54.02 (51.67 to 56.37) | |
D statistic | 2.32 (2.30 to 2.34) | 2.22 (2.11 to 2.32) | |
ROC statistic | 0.875 (0.872 to 0.877) | 0.818 (0.803 to 0.833) | |
QResearch cohort
| |||
R2 statistic (%) | 56.45 (55.40 to 57.50) | 55.39 (0.52.59 to 58.18) | |
D statistic | 2.33 (2.28 to 2.40) | 2.28 (2.15 to 2.41) | |
ROC statistic | 0.877 (0.873 to 0.880) | 0.843 (0.825 to 0.860) | |
Men
|
THIN cohort
| ||
R2 statistic (%) | 57.41 (54.56 to 60.27) | 52.86 (50.55 to 55.17) | |
D statistic | 2.38 (2.24 to 2.51) | 2.17 (2.07 to 2.27) | |
ROC statistic | 0.875 (0.873 to 0.878) | 0.839 (0.827 to 0.850) | |
QResearch cohort
| |||
R2 statistic (%) | 58.29 (55.31 to 61.26) | 56.65 (53.94 to 59.35) | |
D statistic | 2.42 (2.28 to 2.56) | 2.34 (2.21 to 2.47) | |
ROC statistic | 0.878 (0.874 to 0.882) | 0.846 (0.829 to 0.862) |