Variability in the incidence of renal replacement therapy over time in Western industrialized countries: A retrospective registry analysis

Introduction

A growing number of patients started renal replacement therapy (RRT) in Western industrialized countries between 1980 an early 2000s. Thereafter reports from national and international registries suggest a trend towards stabilization and sometimes a decrease in the incidence rate.

Aim

To investigate the differences in overall and age-specific incidence rates between industrialized countries from 1998 until 2013. Secondly, to investigate changes in incidence rates over time and their association with specific age categories.

Method

We extracted the unadjusted overall incidence of RRT and age-specific incidence rates from renal registry reports in Europe, the United States, Canada, Australia and New Zealand. Time trends in the incidence rate by country and age categories were analyzed by Joinpoint regression analysis.

Results

The incidence rate in 2013 ranged from 89 per million population (pmp) in Finland to 363 pmp in the US. Incidence rates in the lower age categories (20–64 year) were similar between countries and remained stable over time. Higher incidence countries were characterized by higher numbers of patients in both the 65–74 and ≥75 year categories starting RRT.

Joinpoint analysis confirmed that most countries had significant reductions in the incidence rate at the end of the study period. These reductions were explained by lower numbers of older patients starting RRT and were observed also in countries with lower overall incidence rates.

Conclusion

This study confirmed different incidence rates of RRT between industrialized countries worldwide. Countries with the highest overall incidence rates also had the highest incidence rates in the oldest age categories. Since the early 2000’s the number of older patients starting RRT is either stabilizing or even decreasing in most countries. This reduction is universal and is also observed in countries with previously low incidence rates.

The increase in renal replacement therapy (RRT) incidence has come to an end in Sweden-analysis of variations by region over the period 1991-2010

BACKGROUND

Renal replacement therapy (RRT) incidence has increased significantly in Sweden during the past decades. This study analyses variations in time and regional trends in RRT incidence in Sweden, adjusted for age and gender, focusing on the impact change in incidence during the last decade.

METHODS

Using data from the Swedish Renal Registry (SRR) (21 counties in Sweden, total population 9 million), we identified all incident subjects starting RRT from 1991 through 2010. Only individuals alive following 90 days of RRT start were included. Gender- and age-specific standardized RRT incidences on an annual and regional basis were calculated, and differences between counties and variations over time were examined. We compared the overall age and gender-adjusted RRT incidence rates for Sweden by calendar year. Furthermore, we also calculated the age and gender-adjusted RRT incidence in each county during two time periods (1991-1999 versus 2000-2010).

RESULTS

There were 20 172 new subjects treated with RRT between January 1991 and December 2010. The most common cause of end-stage renal disease (ESRD) was diabetes (24%) and hypertension/renal vascular disease (19%), followed by glomerulonephritis (16%). Sixty-four percent of new patients were male; the median age when commencing RRT was 66 years (10-90 percentiles; 39-80). The overall standardized RRT incidence reached its peak in 2000, and slowly decreased thereafter. A decrease in RRT incidence was observed over the study period in eight regions. The standardized RRT incidence varied between the different counties, from 0.82 to 1.19.

CONCLUSIONS

Adjusted for demographic changes in the population, an overall decrease in RRT incidence was observed from the year 2000 onwards-suggesting that the previously reported steady increase in RRT incidence is coming to an end in Sweden. Noteworthy differences were found between counties and in 8 out of 21 counties, a decreased incidence of RRT was found. Further studies need to identify the factors that contribute to this decrease.