The 1-year risk of death from any cause was substantially higher at lower eGFR levels even after accounting for any differences in age and sex in a large, community-based population receiving care within an integrated health care delivery system in northern California. However, across all eGFR levels, there were favorable temporal trends in all-cause mortality between 2000 and 2008. Importantly, the absolute improvement in 1-year mortality during the analysis period was greater among those starting with worse kidney function. The focus of these analyses was on CKD before the onset of ESRD, so information was not available on death rates in patients receiving chronic dialysis or renal transplant.
Chart Explanation: The age-sex-adjusted risk of death at 1 year was higher with lower eGFR levels in each calendar year between 2000 and 2008 in a large, community-based population receiving care within an integrated health care delivery system in northern California. However, in all eGFR categories, there was a favorable trend in lower mortality over time. The focus of these analyses was on CKD prior to onset of ESRD, so information was not available on death rates in patients receiving chronic dialysis or a renal transplant.
The source population was Kaiser Permanente Northern California, a large integrated health care delivery system that provides comprehensive inpatient and outpatient care for >3.2 million members in the San Francisco and greater Bay Area. The Kaiser Permanente Northern California population is highly representative of the local surrounding and statewide population with regards to age, gender, race/ethnicity and comorbidity burden, with only slightly lower representation at the extremes of age and income. The study samples included all adult health plan members aged 40 years or older as of January 1st of each calendar year of interest and who had known eGFR of 150 ml/min/1.73 m2 or less based on ambulatory, non-emergency department serum creatinine measures found in health plan databases. Estimated GFR was calculated using the CKD-EPI equation. Given the focus on CKD before the onset of ESRD, all patients with prior chronic dialysis or receipt of renal transplant were excluded.
For each calendar year’s eligible cohort, patients were stratified by eGFR category (90-150, 60-89, 45-59, 30-44, 15-29 and <15 ml/min/1.73 m2 not receiving renal replacement therapy). Given the relatively low frequency of testing for urine protein excretion, albuminuria was not included in these analyses. Death from any cause was identified from a comprehensive merged mortality file using data from Kaiser Permanente Northern California administrative and hospitalization databases, Social Security Administration vital status files and California State death certificate files through December 31, 2008. The 1-year risk of death was calculated by calendar year for each eGFR category and adjusted for age and sex using direct adjustment methods and the 2008 cohort as the referent group.
This material is the result of work supported with resources from the Centers for Disease Control as well as Kaiser Permanente Northern California, Oakland, CA.
| Field | Data |
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| Description of Measure | Age-sex-adjusted 1-year risk of all-cause death |
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| Data Source | Kaiser Permanente Northern California electronic medical record system, Social Security Administration vital status files, California State death certificate files |
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| Type of Data Source | Clinical, demographic and vitals status data |
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| Data Set | Kaiser Permanente Northern California adult members aged ≥40 years with eGFR <=150 ml/min/1.73 m2 between January 1, 2000 and December 31, 2008 |
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| Health Care System Data | Yes |
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| Regional or National? | Regional |
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| Demographic Group | Kaiser Permanente Northern California adult members aged ≥40 years with eGFR ≤150 ml/min/1.73 m2 between January 1, 2000 and December 31, 2008 |
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| Numerator | Patients in denominator who died in the calendar year |
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| Denominator | Patients aged ≥40 years who had eGFR ≤150 ml/min/1.73 m2 as of January 1st of the calendar year of interest |
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| Primary Data Source Indicator | Death date |
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| Primary Indicator Method of Measurement | The date of death is identified from a comprehensive merged mortality file using data from Kaiser Permanente Northern California administrative and hospitalization databases, Social Security Administration vital status files and California State death certificate files |
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| Secondary (1) Variable : Category of eGFR | eGFR 90-150 ml/min/1.73 m² eGFR 60-89 ml/min/1.73 m² eGFR 45-59 ml/min/1.73 m², eGFR 30-44 ml/min/1.73 m², eGFR 15-29 ml/min/1.73 m², and <15 ml/min/1.73 m² not receiving dialysis or renal transplant |
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| Glomerular Filtration Rate | Estimated using the CKD-EPI equation: |
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| Frequency of Measurement (Primary) | Once per qualifying calendar year |
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| Period Currently Available | 2008 |
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| Limitations of Indicator | Given the focus on CKD before the onset of ESRD, information on patients receiving chronic dialysis or a renal transplant is not included. |
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