The study was financially sponsored by Boehringer Ingelheim Pharmaceuticals Inc. and Eli Lilly and Co., but the National Kidney Foundation was responsible for the design and conduct of the study; collection, management, analysis and interpretation of the data; and preparation, review and approval of the manuscript. Richard J. Deloskey and Hsu-Lin Su are employed by Covance Inc. Compensation at Covance is not dependent on the results of the study presented in the manuscript. Lynda A. Szczech is a nephrologist employed by Durham Nephrology Associates. Her compensation is not dependent on the results of the study presented in the manuscript. These interests do not alter the authors' adherence to all PLOS ONE policies on sharing data and materials.
Conceived and designed the experiments: LS RS BA CF PM JV. Performed the experiments: LS RS HLS RJD BA CF PM JV. Analyzed the data: LS RS HLS RJD BA CF PM JV. Contributed reagents/materials/analysis tools: LS RS BA CF PM JV. Wrote the paper: LS RS HLS RJD BA CF PM JV.
This US, multicenter, observational study assessed the CKD prevalence in adult patients with type-2 diabetes mellitus (T2DM) and characterized the proportion of detected and undiagnosed CKD in the primary care setting using the following: a clinician survey; a patient physical exam and medical history; a single blood draw for estimated glomerular filtration rate (eGFR) and glycosolated hemoglobin (HbA1c); urine dipstick for protein; urine albumin-creatinine ratio (ACR); two patient quality of life questionnaires; and a 15-month medical record review. The study consisted of 9339 adults with T2DM and 466 investigator sites. Of the 9339 enrolled, 9307 had complete data collection for analysis. The 15-month retrospective review showed urine protein, urine ACR, and eGFR testing were not performed in 51.4%, 52.9% and 15.2% of individuals, respectively. Of the 9307 patients, 5036 (54.1%) had Stage 1–5 CKD based on eGFR and albuminuria; however, only 607 (12.1%) of those patients were identified as having CKD by their clinicians. Clinicians were more successful in diagnosing patients with Stage 3–5 CKD than Stages 1 and 2. There were no differences in clinicians’ likelihood of identification of CKD based on practice setting, number of years in practice, or self-reported patients seen per week. Awareness or patient self-reported CKD was 81.1% with practitioner detection versus 2.6% in the absence of diagnosis. Primary care of T2DM demonstrates recommended urine CKD testing is underutilized, and CKD is significantly under-diagnosed. This is the first study to show CKD detection is associated with awareness.
Chronic kidney disease (CKD) is common and increasing in prevalence in the US. The estimated proportion of CKD stages 1 to 4 in US adults grew from 10% to 13.1% between 1994 and 2004, based on the National Health and Nutrition Examination Survey (NHANES)
The current criteria for detection of diabetes according to the American Diabetes Association (ADA) includes hemoglobin A1c (HbA1c) ≥6.5%, fasting plasma glucose ≥126 mg/dL (7.0 mmol/L), or a random plasma glucose concentration ≥200 mg/dL (11.1 mmol/L)
Awareness of CKD remains low at 10% in US adults in part because CKD is usually silent until its late stages
This multi-center, observational, cross-sectional study was conducted in 466 primary care practices in a geographic distribution representative of the US between 6/28/11 and 2/06/12. Primary care practitioners were recruited using several mechanisms described in
Patients 18 years of age or older with T2DM for one year or longer were eligible to participate. Key exclusion criteria included current therapy with peritoneal or hemodialysis or a functioning kidney transplant. A consecutive sampling approach was encouraged to minimize selection biases.
After signing informed consent, each patient underwent a blood draw to determine eGFR, and HbA1c, a urine analysis to detect proteinuria, a urine measurement for ACR, and two patient HRQoL questionnaires. A national laboratory, Quest Diagnostics, was utilized for all study related laboratory measurements. At the time of the Study Visit, a physical examination including measurement of weight and waist circumference was conducted. Data were recorded using a secure online electronic data capture (EDC) system.
Sample size calculations suggested that approximately 9660 patients with T2DM would need to be enrolled to achieve adequate precision in estimating the rate of undiagnosed CKD by stage.
Estimated glomerular filtration rate was calculated using the study measured value of isotope dilution mass spectrometry-traceable serum creatinine using the CKD-EPI equation
After the study visit, all patients’ medical records over the prior 15 months were reviewed to determine if their PCP had documented the presence of any stage of CKD in a clinical note or a billing diagnosis. In addition, a review of selected laboratory data and medications prescribed was also completed. Using the study laboratory derived stage of CKD as the “gold standard”, each patient's correct or incorrect designation as having CKD based on clinical notes and billing diagnoses was determined. Based on this evaluation, each patient was described as either a true positive, true negative, false positive or false negative patient (as defined in
Parameter | CKD by Study Laboratory Results at Study Visit | Normal Kidney Function by Study Laboratory Results at Study Visit | |||
Total of Assessed Patients | True Positive | False Negative | True Negative | False Positive | |
(N = 9307)a | (N = 607) | (N = 4429) | (N = 4213) | (N = 58) | |
N/A | 6.5% | 47.6% | 45.3% | 0.6% | |
No CKD (eGFR ≥60 with no protein excretion) | 4271 (45.9) | 0 | 0 | 4213 (100.0) | 58 (100.0) |
1 (eGFR ≥90 with abnormal protein excretion) | 1038 (11.2) | 11 (1.8) | 1027 (23.2) | 0 | 0 |
2 (eGFR: 60–89 with abnormal protein excretion): Mild | 1602 (17.2) | 79 (13.0) | 1523 (34.4) | 0 | 0 |
3 (eGFR: 30–59): Moderate | 2156 (23.2) | 389 (64.1) | 1767 (39.9) | 0 | 0 |
4 (eGFR: 15–29): Severe | 223 (2.4) | 118 (19.4) | 105 (2.4) | 0 | 0 |
5 (eGFR <15 or dialysis): Kidney Failure | 17 (0.2) | 10 (1.6) | 7 (0.2) | 0 | 0 |
Overall (Stage 2–5): Mild to Kidney Failure | 3998 (43.0) | 596 (98.2) | 3402 (76.8) | 0 | 0 |
Overall (Stage 1–5) | 5036 (54.1) | 607 (100.0) | 4429 (100.0) | 0 | 0 |
Abbreviations: ACR = albumin/creatinine ratio; CKD = chronic kidney disease; eGFR = estimated glomerular filtration rate; N = number of patients; N/A = not applicable.
True Positive: Patients who reported as diagnosed with CKD (on CKD History eCRF page) and with actual presence of CKD based on laboratory results from the Study Visit;
True Negative: Patients who reported as not diagnosed with CKD (on CKD History eCRF page) and without actual presence of CKD based on laboratory results from the Study Visit;
False Positive: Patients who reported as diagnosed with CKD (on CKD History eCRF page) and without actual presence of CKD based on laboratory results from the Study Visit;
False Negative: Patients who reported as not diagnosed with CKD (on CKD History eCRF page) and with actual presence of CKD based on laboratory results from the Study Visit.
a: A total of 9339 patients enrolled in the study, but only 9307 patients had the laboratory test results and medical history records to assess as True Positive, True Negative, False Positive, or False Negative for CKD.
b: If eGFR, urine dipstick, and urine ACR data were all available:
•No CKD: Normal eGFR (≥60 mL/min/1.73 m2) with neither positive protein in urine nor urine ACR ≥30 mg/g.
•Stage 1: Normal eGFR (≥90 mL/min/1.73 m2) with either positive protein in urine or urine ACR ≥30 mg/g.
•Stage 2: eGFR 60 to 89 mL/min/1.73 m2 with either positive protein in urine or urine ACR ≥30 mg/g.
•Stage 3: eGFR = 30 to 59 mL/min/1.73 m2;
•Stage 4: eGFR = 15to 29 mL/min/1.73 m2; and
•Stage 5: eGFR <15 mL/min/1.73 m2 (Stages 3, 4, 5 were based on eGFR value alone).
If eGFR, urine dipstick, and urine ACR data were not all available: classify with the worst CKD stage based on the available data from eGFR, urine dipstick, and/or urine ACR.
Among sites that enrolled 10 or more patients, the Q1 (25th percentile), median, and Q3 (75th percentile) sensitivity for diagnosing CKD in patients with CKD established using study related labs were 0, 6.3, and 16.7%. Because this distribution was skewed with the tail to the right, sensitivities were categorized as 0%, >0% to <50%, and ≥50% to compare PCP characteristics.
To assess patients' current state of CKD awareness, patients were asked “Have you ever been told by a doctor or other health care professional that you have a chronic kidney disease (a decreased GFR, or elevated serum creatinine, or weak and/or failing kidneys)?”
Data were summarized overall and among patient subgroups based on true positive, true negative, false positive, and false negative categories. Discrete and ordinal variables were summarized by frequencies and percentages [n (%)], whereas continuous variables were summarized by mean, standard deviation (SD), median, 25th and 75th percentiles, minimum, and maximum.
All analyses were performed using the SAS statistical software package (Version 9.1, Cary, NC).
A total of 9339 patients were enrolled at 466 US practices. Of these, 9307 (99.7%) patients could be assessed for the presence of CKD, and 9204 (98.6%) completed all aspects of the study. Of the 9307 patients with laboratory data, 54.1% had CKD (
When comparing patients with CKD identified prior to study enrollment by their PCP (True Positives) to those with CKD who were not identified as having CKD prior to study enrollment (False Negatives) and to those without CKD (True Negatives and False Positives), there were few differences (
Parameter | CKD by Study Laboratory Results at Study Visit | Normal Kidney Function by Study Laboratory Results at Study Visit | |||
True | False | True | False | ||
Total | Positive | Negative | Negative | Positive | |
(N = 9339)a | (N = 607) | (N = 4429) | (N = 4213) | (N = 58) | |
n (%) | n (%) | n (%) | n (%) | n (%) | |
18–24 | 12 (0.1) | 0 | 5 (0.1) | 7 (0.2) | 0 |
25–34 | 114 (1.2) | 0 | 44 (1.0) | 68 (1.6) | 0 |
35–44 | 573 (6.1) | 9 (1.5) | 227 (5.1) | 333 (7.9) | 2 (3.4) |
45–54 | 1621(17.4) | 31 (5.1) | 636 (14.4) | 942 (22.4) | 9 (15.5) |
55–64 | 2867 (30.7) | 121 (19.9) | 1256 (28.4) | 1462 (34.7) | 19 (32.8) |
65–74 | 2717 (29.1) | 250 (41.2) | 1363 (30.8) | 1077 (25.6) | 15 (25.9) |
≥75 | 1434 (15.4) | 196 (32.3) | 897 (20.3) | 324 (7.7) | 13 (22.4) |
Missing | 1 (0.0) | 0 | 1 (0.0) | 0 | 0 |
Male | 4580 (49.0) | 313 (51.6) | 2207 (49.8) | 2017 (47.9) | 27 (46.6) |
Female | 4759 (51.0) | 294 (48.4) | 2222 (50.2) | 2196 (52.1) | 31 (53.4) |
White | 6972 (74.7) | 471 (77.6) | 3343 (75.5) | 3090 (73.3) | 45 (77.6) |
Black or African American | 1579 (16.9) | 93 (15.3) | 734 (16.6) | 740 (17.6) | 10 (17.2) |
American Indian or Alaska Native | 32 (0.3) | 1 (0.2) | 13 (0.3) | 18 (0.4) | 0 |
Asian, Native Hawaiian, or other Pacific Islander | 371 (4.0) | 19 (3.1) | 166 (3.7) | 180 (4.3) | 2 (3.4) |
Other | 379 (4.1) | 23 (3.8) | 170 (3.8) | 184 (4.4) | 1 (1.7) |
Missing | 6 (0.1) | 0 | 3 (0.1) | 1 (0.0) | 0 |
Hispanic or Latino | 1231 (13.2) | 67 (11.0) | 560 (12.6) | 589 (14.0) | 8 (13.8) |
Not Hispanic or Latino | 8102 (86.8) | 540 (89.0) | 3866 (87.3) | 3623 (86.0) | 50 (86.2) |
Missing | 6 (0.1) | 0 | 3 (0.1) | 1 (0.0) | 0 |
n | 9332 | 606 | 4427 | 4211 | 58 |
Mean | 33.7 | 33.5 | 33.8 | 33.8 | 33.1 |
SD | 7.6 | 7.6 | 7.7 | 7.5 | 7.4 |
Still smoke | 1218 (13.0) | 53 (8.7) | 572 (12.9) | 583 (13.8) | 7 (12.1) |
Used to smoke | 3423 (36.7) | 260 (42.8) | 1631 (36.8) | 1497 (35.5) | 21 (36.2) |
Missing | 4698 (50.3) | 294 (48.4) | 2226 (50.3) | 2133 (50.6) | 30 (51.7) |
Yes | 676 (7.2) | 492 (81.1) | 117 (2.6) | 31 (0.7) | 34 (58.6) |
No | 8656 (92.7) | 115 (18.9) | 4308 (97.3) | 4181 (99.2) | 24 (41.4) |
Missing | 7 (0.1) | 0 | 4 (0.1) | 1 (0.0) | 0 |
Yes | 7605 (81.4) | 571 (94.1) | 3750 (84.7) | 3215 (76.3) | 48 (82.8) |
No | 1727 (18.5) | 36 (5.9) | 675 (15.2) | 997 (23.7) | 10 (17.2) |
Missing | 7 (0.1) | 0 | 4 (0.1) | 1 (0.0) | 0 |
Yes | 7297 (78.1) | 532 (87.6) | 3487 (78.7) | 3210 (76.2) | 45 (77.6) |
No | 2035 (21.8) | 75 (12.4) | 938 (21.2) | 1002 (23.8) | 13 (22.4) |
Missing | 7 (0.1) | 0 | 4 (0.1) | 1 (0.0) | 0 |
Yes | 3740 (40.0) | 358 (59.0) | 1940 (43.8) | 1398 (33.2) | 30 (51.7) |
No | 5582 (59.8) | 249 (41.0) | 2482 (56.0) | 2807 (66.6) | 28 (48.3) |
Missing | 17 (0.2) | 0 | 7 (0.2) | 8 (0.2) | 0 |
Note: Denominators for percentages are based on the number of enrolled patients.
Abbreviations: BMI = body mass index; CKD = chronic kidney disease; eCRF = estimated glomerular filtration rate; N = number of patients; SD = standard deviation.
For definitions of True Positive, True Negative, False Positive, and False Negative CKD assessment categories,
a: A total of 9339 patients enrolled in the study, but only 9307 patients had the laboratory test results and medical history records to assess as True Positive, True Negative, False Positive, or False Negative for CKD.
b: Age is calculated as (informed consent date - date of birth)/365.25 and reported as whole years.
c: BMI (kg/m2) is calculated as (Weight(kg)/Height(m)2)
d: If patient checked "Yes" for heart angina, heart attack, heart bypass surgery, heart angioplasty, stroke, heart failure, abnormal heart rhythm, or coronary artery disease on Medical History eCRF page.
With respect to the self-reported presence of CKD, few patients in the True Negative and False Negative Groups reported the presence of kidney disease (0.7 and 2.6%, respectively) while the majority of patients in the True Positive group reported knowing that they had kidney disease (81.1%). The proportion of patients reporting concurrent comorbid conditions such as hypertension, hypercholesterolemia, and cardiovascular disease was consistently greater in the True Positive group.
Of the 445 PCPs who enrolled at least 10 patients, 19 (4.3%) had ≥50% likelihood of identifying patients with CKD, 217 (48.8%) had a likelihood of <50%, and 209 (47.0%) didn't identify any of their CKD patients (had a 0% sensitivity).
The patient specific demographic and clinical factors that influenced clinicians to screen for CKD were similar among the groups based on sensitivity (
Parameter | Sensitivity |
||
0% | >0 to <50% | ≥50% | |
(N = 209) | (N = 217) | (N = 19) | |
Age | 161 (77.0) | 160 (73.7) | 16 (84.2) |
Gender | 65 (31.1) | 54 (24.9) | 6 (31.6) |
Race | 115 (55.0) | 107 (49.3) | 9 (47.4) |
Presence of T2DM | 204 (97.6) | 213 (98.2) | 19 (100.0) |
Presence of CVD | 146 (69.9) | 154 (71.0) | 15 (78.9) |
Presence of Hypertension | 189 (90.4) | 201 (92.6) | 18 (94.7) |
Family History of Kidney Disease | 163 (78.0) | 170 (78.3) | 18 (94.7) |
Other | 16 (7.7) | 15 (6.9) | 3 (15.8) |
Every 1 Month | 2 (1.0) | 3 (1.4) | 1 (5.3) |
Every 2 Months | 1 (0.5) | 1 (0.5) | 0 (0.0) |
Every 3 Months | 56 (26.8) | 64 (29.5) | 5 (26.3) |
Every 4 Months | 15 (7.2) | 15 (6.9) | 1 (5.3) |
Every 5 Months | 0 (0.0) | 1 (0.5) | 0 (0.0) |
Every 6 Months | 69 (33.0) | 73 (33.6) | 10 (52.6) |
Every 9 Months | 1 (0.5) | 0 (0.0) | 0 (0.0) |
Every 12 Months | 29 (13.9) | 28 (12.9) | 1 (5.3) |
Missing | 36 (17.2) | 32 (14.7) | 1 (5.3) |
Every 1 Month | 5 (2.4) | 5 (2.3) | 1 (5.3) |
Every 2 Months | 0 (0.0) | 2 (0.9) | 1 (5.3) |
Every 3 Months | 30 (14.4) | 34 (15.7) | 2 (10.5) |
Every 4 Months | 6 (2.9) | 8 (3.7) | 0 (0.0) |
Every 6 Months | 36 (17.2) | 30 (13.8) | 0 (0.0) |
Every 12 Months | 61 (29.2) | 50 (23.0) | 3 (15.8) |
Missing | 71 (34.0) | 88 (40.6) | 12 (63.2) |
Every 1 Month | 1 (0.5) | 2 (0.9) | 0 (0.0) |
Every 2 Months | 0 (0.0) | 2 (0.9) | 0 (0.0) |
Every 3 Months | 17 (8.1) | 22 (10.1) | 2 (10.5) |
Every 4 Months | 4 (1.9) | 7 (3.2) | 0 (0.0) |
Every 5 Months | 2 (1.0) | 0 (0.0) | 0 (0.0) |
Every 6 Months | 37 (17.7) | 29 (13.4) | 5 (26.3) |
Every 9 Months | 1 (0.5) | 0 (0.0) | 0 (0.0) |
Every 12 Months | 66 (31.6) | 75 (34.6) | 8 (42.1) |
Every 24 Months | 1 (0.5) | 0 (0.0) | 0 (0.0) |
Missing | 80 (38.3) | 80 (36.9) | 4 (21.1) |
<30 | 7 (3.3) | 12 (5.5) | 0 (0.0) |
<40 | 10 (4.8) | 0 (0.0) | 0 (0.0) |
<45 | 4 (1.9) | 3 (1.4) | 0 (0.0) |
<50 | 24 (11.5) | 21 (9.7) | 3 (15.8) |
<55 | 4 (1.9) | 9 (4.1) | 0 (0.0) |
<59 | 7 (3.3) | 13 (6.0) | 1 (5.3) |
<60 | 120 (57.4) | 130 (59.9) | 14 (73.7) |
<65 | 1 (0.5) | 2 (0.9) | 0 (0.0) |
<70 | 1 (0.5) | 2 (0.9) | 0 (0.0) |
<75 | 2 (1.0) | 1 (0.5) | 0 (0.0) |
<80 | 2 (1.0) | 5 (2.3) | 0 (0.0) |
<90 | 19 (9.1) | 15 (6.9) | 1 (5.3) |
<100 | 4 (1.9) | 2 (0.9) | 0 (0.0) |
Missing | 4 (1.9) | 2 (0.9) | 0 (0.0) |
+1 | 110 (52.6) | 93 (42.9) | 12 (63.2) |
+2 | 44 (21.1) | 56 (25.8) | 5 (26.3) |
+3 | 24 (11.5) | 23 (10.6) | 2 (10.5) |
+4 | 5 (2.4) | 6 (2.8) | 0 (0.0) |
trace | 22 (10.5) | 36 (16.6) | 0 (0.0) |
Missing | 4 (1.9) | 3 (1.4) | 0 (0.0) |
>0 | 10 (4.8) | 8 (3.7) | 0 (0.0) |
>1 | 5 (2.4) | 7 (3.2) | 1 (5.3) |
>2 | 8 (3.8) | 7 (3.2) | 0 (0.0) |
>3 | 3 (1.4) | 4 (1.8) | 0 (0.0) |
>4 | 0 (0.0) | 1 (0.5) | 0 (0.0) |
>5 | 6 (2.9) | 4 (1.8) | 0 (0.0) |
>10 | 4 (1.9) | 2 (0.9) | 0 (0.0) |
>15 | 1 (0.5) | 2 (0.9) | 0 (0.0) |
>16 | 0 (0.0) | 1 (0.5) | 0 (0.0) |
>20 | 7 (3.3) | 6 (2.8) | 1 (5.3) |
>23 | 2 (1.0) | 0 (0.0) | 1 (5.3) |
>25 | 0 (0.0) | 4 (1.8) | 0 (0.0) |
>29 | 2 (1.0) | 0 (0.0) | 0 (0.0) |
>30 | 114 (54.5) | 115 (53.0) | 11 (57.9) |
>31 | 0 (0.0) | 1 (0.5) | 0 (0.0) |
>35 | 3 (1.4) | 2 (0.9) | 1 (5.3) |
>40 | 1 (0.5) | 1 (0.5) | 0 (0.0) |
>50 | 5 (2.4) | 4 (1.8) | 0 (0.0) |
>60 | 2 (1.0) | 1 (0.5) | 0 (0.0) |
>80 | 0 (0.0) | 1 (0.5) | 0 (0.0) |
>84 | 1 (0.5) | 0 (0.0) | 0 (0.0) |
>100 | 4 (1.9) | 5 (2.3) | 0 (0.0) |
>150 | 2 (1.0) | 1 (0.5) | 0 (0.0) |
>200 | 5 (2.4) | 2 (0.9) | 0 (0.0) |
>250 | 1 (0.5) | 1 (0.5) | 0 (0.0) |
>299 | 1 (0.5) | 1 (0.5) | 0 (0.0) |
>300 | 14 (6.7) | 30 (13.8) | 3 (15.8) |
Missing | 8 (3.8) | 6 (2.8) | 1 (5.3) |
>0 | 15 (7.2) | 11 (5.1) | 0 (0.0) |
>1 | 6 (2.9) | 8 (3.7) | 1 (5.3) |
>2 | 14 (6.7) | 18 (8.3) | 2 (10.5) |
>3 | 9 (4.3) | 12 (5.5) | 1 (5.3) |
>4 | 0 (0.0) | 3 (1.4) | 0 (0.0) |
>5 | 8 (3.8) | 2 (0.9) | 0 (0.0) |
>6 | 0 (0.0) | 0 (0.0) | 1 (5.3) |
>9 | 0 (0.0) | 0 (0.0) | 1 (5.3) |
>10 | 8 (3.8) | 7 (3.2) | 0 (0.0) |
>15 | 2 (1.0) | 5 (2.3) | 0 (0.0) |
>16 | 1 (0.5) | 0 (0.0) | 0 (0.0) |
>20 | 5 (2.4) | 7 (3.2) | 0 (0.0) |
>24 | 0 (0.0) | 0 (0.0) | 1 (5.3) |
>25 | 0 (0.0) | 1 (0.5) | 0 (0.0) |
>30 | 49 (23.4) | 52 (24.0) | 3 (15.8) |
>35 | 4 (1.9) | 2 (0.9) | 1 (5.3) |
>44 | 1 (0.5) | 0 (0.0) | 0 (0.0) |
>45 | 3 (1.4) | 2 (0.9) | 1 (5.3) |
>50 | 6 (2.9) | 5 (2.3) | 0 (0.0) |
>60 | 0 (0.0) | 2 (0.9) | 0 (0.0) |
>80 | 0 (0.0) | 1 (0.5) | 0 (0.0) |
>84 | 4 (1.9) | 5 (2.3) | 0 (0.0) |
>85 | 2 (1.0) | 0 (0.0) | 0 (0.0) |
>90 | 1 (0.5) | 0 (0.0) | 0 (0.0) |
>100 | 9 (4.3) | 6 (2.8) | 1 (5.3) |
>120 | 0 (0.0) | 0 (0.0) | 1 (5.3) |
>130 | 0 (0.0) | 1 (0.5) | 0 (0.0) |
>150 | 3 (1.4) | 6 (2.8) | 0 (0.0) |
>200 | 25 (12.0) | 22 (10.1) | 2 (10.5) |
>250 | 0 (0.0) | 1 (0.5) | 0 (0.0) |
>275 | 0 (0.0) | 1 (0.5) | 0 (0.0) |
>299 | 1 (0.5) | 0 (0.0) | 0 (0.0) |
>300 | 21 (10.0) | 28 (12.9) | 1 (5.3) |
Missing | 12 (5.7) | 8 (3.7) | 2 (10.5) |
Abbreviations: ACR = albumin/creatinine ratio; CKD = chronic kidney disease; CVD = cardiovascular disease; eGFR = estimated glomerular filtration rate; N = number of patients; T2DM = type 2 diabetes mellitus.
. Only sites with at least 10 enrolled patients were included for this analysis. Sensitivity for each investigator site was defined as (No. of True Positive)/(No. of True Positive + No. of False Negative) x 100%.
. Provider could check more than one category.
When asked what eGFR value indicates that a patient has CKD, the greatest proportion of PCPs reported an eGFR of <60 mL/min/1.73 m2 was the threshold value with a smaller number reporting a threshold eGFR value of <90 mL/min/1.73 m2. While there were no significant differences among groups overall, a small but significant proportion of clinicians in each category reported <50 mL/min/1.73 m2 as the threshold. There were too few nurse practitioners, 33, to allow for meaningful comparisons versus physicians.
When asked what level of urine albumin excretion indicates that a patient has CKD, the greatest proportion of PCPs (53.9%) reported an ACR of>30 mg/gm as the threshold value above which a patient has CKD. The proportion reporting this value was roughly equivalent among sensitivity categories, while the remainder of PCPs reported values that were higher or lower than the expected value. When asked what level of proteinuria on dipstick urine analysis indicates that a patient has CKD, more than half of all providers reported trace or +1. However, significant proportions that did not differ among categories of sensitivity also reported thresholds of +2 or +3.
During the 15 months prior to study participation, 15.2% of the patients enrolled in this study did not have an eGFR test performed and 31.0% did not have a test for either proteinuria or ACR (51.4% did not have a test for proteinuria and 52.9% did not have an urine ACR measured).
This study quantified the degree to which CKD was recognized in a population of patients at a higher risk due to the presence of T2DM. More than half of participants had CKD as manifested by changes in urine protein excretion, a decreased eGFR, or both. However, among those patients with CKD only 12.1% had their CKD documented as either a diagnosis code or description in the fifteen month chart review.
Clinicians were more successful in recognizing CKD in more advanced stages (e.g., 3 and 4), but still missed nearly half of patients with stage 4 CKD. Fewer than 5% of clinicians achieved a sensitivity of ≥50% with nearly half of all PCPs not applying the diagnosis in any of their patients with CKD. Few differences were identified in approaches to screening for CKD, and interpretations of the screening test results closely resembled the current clinical practice guidelines. PCPs were consistent with the guidelines with regard to the measurement of serum creatinine (eGFR). However, in spite of their acknowledgment of the importance of assessing urine for abnormal levels of protein excretion, 69% of patients had proteinuria tests in the 15 months prior to participation.
The prevalence of CKD found in this cohort is similar to that described among all patients with T2DM in the US (NHANES dataset)
The lowest proportions of patients were identified in stages with relatively preserved eGFR where CKD is defined by the presence of proteinuria/albuminuria, corresponding to lower urinary testing. Multiple studies suggest that proteinuria is a powerful tool to risk stratify patients not only for the progression of their kidney disease but also for cardiovascular and all-cause mortality
This study provides insight into the key points in the delivery of healthcare where identification of CKD can be improved; however, it is not without limitation that may affect the accuracy of the estimates. All stages CKD could have been overestimated, since the single study assessment of ACR and eGFR was not confirmed for a period of>3 months as recommended by CKD clinical practice guidelines. Moreover, the ADA recommends 3 determinations of albuminuria over a six month interval. Thus, the clinician under-detection of CKD is not surprising based on the test results available for review. However, there was indeed remarkable underutilization of the eGFR in 15.2% and ACR in 52.9% tests in the 15 month retrospective data review, despite annual recommendations for people with type-2 diabetes from the NKF
Anita Viliusis was invaluable in administrative support of manuscript preparation and formatting.