Functional status of elderly adults before and after initiation of dialysis

Abstract

Background: It is unclear whether functional status before dialysis is maintained after the initiation of this therapy in elderly patients with end-stage renal disease (ESRD).

Methods: Using a national registry of patients undergoing dialysis, which was linked to a national registry of nursing home residents, we identified all 3702 nursing home residents in the United States who were starting treatment with dialysis between June 1998 and October 2000 and for whom at least one measurement of functional status was available before the initiation of dialysis. Functional status was measured by assessing the degree of dependence in seven activities of daily living (on the Minimum Data Set-Activities of Daily Living [MDS-ADL] scale of 0 to 28 points, with higher scores indicating greater functional difficulty).

Results: The median MDS-ADL score increased from 12 during the 3 months before the initiation of dialysis to 16 during the 3 months after the initiation of dialysis. Three months after the initiation of dialysis, functional status had been maintained in 39% of nursing home residents, but by 12 months after the initiation of dialysis, 58% had died and predialysis functional status had been maintained in only 13%. In a random-effects model, the initiation of dialysis was associated with a sharp decline in functional status, indicated by an increase of 2.8 points in the MDS-ADL score (95% confidence interval [CI], 2.5 to 3.0); this decline was independent of age, sex, race, and functional-status trajectory before the initiation of dialysis. The decline in functional status associated with the initiation of dialysis remained substantial (1.7 points; 95% CI, 1.4 to 2.1), even after adjustment for the presence or absence of an accelerated functional decline during the 3-month period before the initiation of dialysis.

Conclusions: Among nursing home residents with ESRD, the initiation of dialysis is associated with a substantial and sustained decline in functional status.

Figure 1. Decline in Functional Status and Cumulative Mortality among Nursing Home Residents before and after the Initiation of Dialysis

Panel A shows the percentage of 3702 nursing home residents who underwent assessments of activities of daily living (ADL) during 3-month intervals before and after the initiation of dialysis. The cumulative mortality rates were 24% at 3 months, 41% at 6 months, 51% at 9 months, and 58% at 12 months after the initiation of dialysis. Panel B shows the distribution of Minimum Data Set–ADL (MDS–ADL) scores among nursing home residents before and after the initiation of dialysis. Higher MDS–ADL scores indicate poorer functional status. The dashed vertical line indicates the initiation of dialysis.

Figure 2. Change in Functional Status after Initiation of Dialysis

Data were missing for 549 nursing home residents at 3 months, 696 residents at 6 months, 823 residents at 9 months, and 787 residents at 12 months from the full analytic cohort of 3702 residents.

Figure 3. Smoothed Trajectory of Functional Status before and after the Initiation of Dialysis and Cumulative Mortality Rate

The dashed vertical line indicates the initiation of dialysis in a hypothetical 75-year-old nursing home resident. MDS–ADL denotes Minimum Data Set–Activities of Daily Living. The numbers on the MDS–ADL axis run from highest to lowest.