Two - Incidence & prevalence
Growth of the end-stage renal disease (ESRD) program is typically characterized by assessment of total patient counts at a single point in time (point prevalence), of new cases accepted for treatment (incidence), and of patients receiving kidney transplants. Disease rates are computed based on the number of patients per million people in the general population, and are adjusted for age, gender, and race. This year we update our projections using data available through December 31, 2007, and compare results for incidence, prevalence, and mortality both to projections presented in our 2005 JASN paper, which used data through 2000, and to those in the 2008 ADR, using data through 2006. Current projections are down slightly compared to those shown last year, and to results presented in the paper for 2015. The primary reason for these differences is a continued flattening of incident rates in most age and race groups. The 2006 growth in the incident population reversed in 2007, with rates returning to the flattened level seen since 2001. Although the incidence of ESRD due to diabetes has increased among younger minority patients, rates have been stable or falling in older populations and among whites (see Figure 1.21 in Chapter One), showing that a detailed assessment of subpopulations is required to determine whether trends are consistent across all groups defined by age, gender, race, ethnicity, and cause of ESRD. A new finding this year is that the number of elderly patients and those age 45–64 appears to have peaked, though this will require additional years of data to confirm. By race, data on incidence generally show the same flattening as the overall ESRD rates, though rates have been falling among Native Americans. This trend is not universal, however, as incidence among Native Americans younger than 40 has been on the rise. By primary cause, the adjusted rate of new ESRD cases due to diabetes fell 3.3 percent in 2007, to 155 per million population. The rate of ESRD due to glomerulonephritis continues to fall, returning to levels seen in the early 1990s. It is not clear if this finding is related to improved blood pressure control and greater use of ACE-Is or ARBs, or if hypertension and diabetes are now so common that there is some misclassification of primary diagnosis. Additional investigations will be needed to assess the care of these patients, and to determine if detection and treatment continue to improve. Data on the median age of incident patients show important trends; the slight decline in the age of white and Asian patients may illustrate an increasing number of patients age 45–64 entering ESRD, a reflection of the expanding number of post-war baby boomers reaching their middle years. In 2007, the adjusted incident rate for patients age 45–64 fell to the same level seen in 2000 — 611 per million population. The rate for those age 75 and older rose 10.4 percent during the same period, to 1,735, and that for patients age 20–44 grew 5.5 percent, to 126. Racial and ethnic discrepancies in ESRD persist, with 2007 incident rates in the African American and Native American populations 3.7 and 1.8 times greater, respectively, than the rate among whites, and the rate in the Hispanic population 1.5 times higher than that of non-Hispanics. Even after adjustments for age and gender, rates of ESRD continue to vary widely across the U.S. This year we update our data on ESRD in the major metropolitan statistical areas (MSAs) of the United States. Among African Americans, for instance, the incidence of ESRD is greatest in the Denver, Colorado area, while for Hispanics it is highest in the MSA centered around Cincinnati, Ohio. These variations may reflect different burdens of chronic kidney disease, as well as regional differences in the use of detection efforts and treatment interventions in populations at risk for kidney failure. The prevalent population age 75 and older has nearly doubled since 1997, now reaching more than 81,000, while the number of patients age 45–64 has grown 82 percent. The population age 20–44, in contrast, is just 16.5 percent larger now than a decade ago. Prevalent rates per million population are growing most quickly among patients age 65 and older, with an overall increase of 24–28 percent since 2000, and of 42 and 57 percent for ages 65–74 and 75 and older, respectively, in the past decade. Regional variations in ESRD prevalence reflect differences in adjusted survival, in part related to higher rates of transplantation in certain areas of the U.S. Still to be determined is whether these data reflect short- or long-term trends, as the emergence of the baby boomers into a senior population will continue to contribute to the growth of the overall ESRD population, even with moderations in disease rates. The growth of diabetes in both the general Medicare population and among younger patients is a concern as well.
In 2007, the incident rate (adjusted for age, gender, and race) of end-stage renal disease fell 2.1 percent, to 354 per million population. This decline, the first since 1995, brought the rate of new ESRD cases back to that seen in 2005. Figure 2.3; see page 365 for analytical methods. Incident ESRD patients.
In 2007, the incident rate of ESRD was 354 per million population (see Table p.a), and geographically averaged 410 per million in the upper quintile — 8.9 percent lower than in 1997. The highest adjusted rates occur in the southern and southwestern portions of the country, in areas along the Mississippi River, and through the Ohio Valley. Figure 2.4; see page 365 for analytical methods. Incident ESRD patients.
Since 2000, the adjusted incident rate of ESRD has grown 10.4 percent for patients age 75 and older, reaching 1,735 per million population in 2007, while the rate for those age 20–44 has increased 5.5 percent, to 126. In the remaining adult age groups, in contrast, the rate has remained quite stable, with 2007 levels 0.1 percent lower for those age 45–64, and 1.2 percent higher for those age 65–74.
By race, incident rates for African Americans and Native Americans in 2007 reached 998 and 495 per million population, respectively — 3.7 and 1.8 times greater than the rate of 273 found among whites. Since 2000, the rate of new ESRD cases has grown 4.6–5.5 percent for Asians and whites; among African Americans, in contrast, it has remained stable.
Thirteen percent of new ESRD patients in 2007 were Hispanic. The incident rate in this population fell from that seen in 2006, to 508 per million population — 1.5 times greater than that found among non-Hispanics.
Diabetes was the primary cause of ESRD for 54 percent of new patients in 2007; one in three patients had a primary diagnosis of hypertension. The incident rate of diabetic ESRD fell 3.3 percent between 2006 and 2007, to 155 per million population — just 0.6 percent greater than the rate seen in 2000. The rate of ESRD caused by hypertension, in contrast, has grown 8.0 percent since 2000, to 99 per million population, while ESRD due to glomerulonephritis has fallen 21.3 percent, to 24.3. Figures 2.5, 2.6, 2.7, & 2.8; see page 365 for analytical methods. Incident ESRD patients.
The incident rate among patients with Medicare Advantage (formerly Medicare + Choice) coverage peaked in 2001, and by 2005 had fallen 6 percent, reaching 1,407 per million population — 35 percent lower than the rate of 2,166 found in the fee-for-service population. More recent data are not yet available. Figure 2.9; see page 365 for analytical methods. Incident ESRD patients.
The median age of the incident ESRD population has changed little since the late 1990s, from a high of 65.0 in 2001 to 64.4 in 2007. By race and ethnicity, the median age ranges from 59.1 among African Americans to 66.8 among whites. Figure 2.10; see page 365 for analytical methods. Incident ESRD patients.
Adjusted for age, gender, and race, the rate of prevalent ESRD cases rose 2.0 percent between 2006 and 2007, reaching 1,665 per million population. While this rate is nearly 18 percent greater than that seen in 2000, the annual rate of growth has remained between 2.0 and 2.3 percent since 2003. Figure 2.11; see page 365 for analytical methods. December 31 point prevalent patients.
In 2007, the prevalent rate of ESRD was 1,665 per million population (see Table p.a), and averaged 1,951 per million population in the upper quintile. With the addition of high rates in the Dakotas, geographic patterns generally parallel those found in the incident population; the highest rates occur in the south and southwestern portions of the country. Figure 2.12; see page 365 for analytical methods. December 31 point prevalent patients.
The adjusted rate of prevalent ESRD cases among patients age 65–74 reached 5,870 per million population in 2007 — nearly 24 percent greater than in 2000. For patients age 75 and older the rate is now 5,124, nearly 28 percent higher than in 2000. Overall growth in the rate during the same period has been just 17.5 percent.
By race, rates of prevalent ESRD continue to be highest in the African American and Native American populations, at 5,111 and 2,713 per million population, respectively, in 2007, compared to 1,222 and 1,911 among whites and Asians. The rate for Hispanic patients reached 2,408 in 2007, 1.5 times greater than the rate of 1,613 seen among non-Hispanics.
By primary diagnosis, annual growth in rates of existing ESRD cases continues to be relatively stable. In 2007, rates for ESRD caused by cystic kidney disease, glomerulonephritis, hypertension, and diabetes reached 79, 260, 407, and 619 per million population, respectively. Figures 2.13, 2.14, 2.15, & 2.16; see page 365 for analytical methods. December 31 point prevalent patients.
The median age of the prevalent ESRD population has grown 2.7 percent since 2000, reaching 59.1 in 2007. By race and ethnicity, it varies from 57.1 in the African American population to 60.3 among whites. Figure 2.17; see page 365 for analytical methods. December 31 point prevalent patients.
By MSA, the greatest adjusted rate of prevalent ESRD for whites occurs in the Los Angeles area, at 1,542 per million population. For African Americans, rates of 6,000–7,400 are found in the St. Louis, Cincinnati, and Pittsburgh MSAs. The St. Louis MSA also has the highest prevalence among Hispanic patients, of 4,122. Table 2.a; see page 365 for analytical methods. Incident & December 31 point prevalent patients, 2007. *Values for cells with ten or fewer patients are suppressed.The overall adjusted rate of ESRD due to diabetes was 155 per million population in 2007, 36 percent higher than a decade before. Both the highest rate and the greatest growth occurred in Network 14, at 193 per million and 53 percent, respectively. The rate of new ESRD cases due to hypertension rose only 2.6 percent in Network 1, but 70 percent in Network 15. And, with the exception of Network 16, rates of ESRD due to glomerulonephritis have fallen across the country. Figures 2.18, 2.19, & 2.20; see page 365 for analytical methods. Incident ESRD patients.
The mean age of both the incident and prevalent ESRD populations is greatest in areas of the Upper Midwest, the Northeast, and Florida. In the lower quintle, the mean age is 59.2 for incident patients, compared to 56.2 in the prevalent population. Means in the upper quintile are 66.7 and 60.4, respectively. Figure 2.21; see page 365 for analytical methods. Incident & December 31 point prevalent patients.
These tables present patient demographics and adjusted disease rates by modality and ESRD network. With an overall incident rate for dialysis patients of 346 per million population in 2007, rates by network range from 228 in Network 16 to 420 in Network 13. The distribution of patients by race continues to vary widely across the country. African Americans, for instance, constitute just 6.6 percent of the new ESRD population in Network 16, but 48–57 percent of patients in Networks 5, 6, and 8.
In the prevalent population, the overall rate for point prevalent dialysis patients in 2007 was 1,163 per million population. Network 1 has the lowest percentage of patients with diabetic ESRD, at 39.4, compared to 52 percent in Networks 14 and 15.
The rate of point prevalent ESRD patients with a transplant is lowest in Network 6, at 390 per million population. In Network 11, in contrast, the rate reaches 758 — 12 percent greater than the next highest rate, found in Network 4. One in nine transplant patients in the U.S. resides in one of the Upper Midwestern states covered by Network 11. Tables 2.b–d; see page 365 for analytical methods. Incident dialysis patients (2.b); December 31 point prevalent dialysis patients (2.c); December 31 point prevalent transplant patients (2.d). *Values for cells with ten or fewer patients are suppressed.