A comparison of infection rates among older and younger patients on continuous peritoneal dialysis.

OBJECTIVE

To determine if peritoneal dialysis-related infection rates are higher in older patients compared with younger patients.

DESIGN

A retrospective review of prospectively collected data. Control adult patients were matched with older study patients for race, sex, insulin dependence, connection device, and time on dialysis.

SETTING

A university-based peritoneal dialysis program which includes patients from a Veterans Administration Hospital outpatient dialysis program.

PATIENTS

Infection rates of 103 patients 60 years of age (older patients) were compared with 103 matched control patients 18-49 years of age (younger patients).

MAIN OUTCOME MEASURES

Rates of peritonitis, exit site and tunnel infection expressed as episodes/patient/year (episodes/year) and the infecting organisms for each were examined. Outcomes, including catheter removal and the cause for removal, transfer to another dialysis modality and the reason for such, death and transplantation were also assessed.

RESULTS

Mean time on peritoneal dialysis was the same in each group (20 +/- 21 months in the older and 18 +/- 17 months in the younger patients). The overall peritonitis rates were the same in the two groups (0.95/year in the older and 0.89/year in the younger patients), but the older patients had a higher rate of S. epidermidis peritonitis (0.28/year vs 0.13/year, p = 0.0001). S. aureus peritonitis rates were similar (0.16/year in older and 0.17/year in younger patients). Older patients had fewer exit-site infections (0.80/year versus 1.2/year, p = 0.0001) and, specifically, lower rates of S. aureus exit-site infections (0.23/year vs 0.47/year, p = 0.0001). Tunnel infections were also less common in older patients (0.15/year vs 0.23/year, p = 0.008), but S. aureus tunnel infection rates were similar (0.05/year and 0.09/year). Catheter infection was the most common reason for catheter removal in both patient groups (35% of catheters in the older and 44% of catheters in the younger patients, p = NS). More catheters were removed form older patients because of dementia or the loss of mechanical skills required to perform peritoneal dialysis exchanges (15% vs 5%, p = 0.04).

CONCLUSIONS

Older age per se is not associated with higher peritonitis rates, but the use of disconnect systems should be encouraged in older patients and their mental and physical skills monitored to avoid S. epidermidis peritonitis. The lower rates of S. aureus catheter infection in older patients requires further study.