Original Investigation
Dialysis
Risk of Stroke in Long-term Dialysis Patients Compared With the General Population

https://doi.org/10.1053/j.ajkd.2013.10.013Get rights and content

Background

Patients undergoing maintenance dialysis are at increased risk of stroke.

Study Design

We performed a nationwide retrospective cohort study to determine the risks for ischemic stroke and hemorrhagic stroke among incident hemodialysis (HD) and peritoneal dialysis (PD) patients in comparison to a reference group in Taiwan.

Setting & Participants

Data for 74,192 HD patients, 5,974 PD patients, and 669,773 nondialysis individuals who were older than 18 years and had no history of stroke or cancer were retrieved from the National Health Insurance Research Database for 1998-2009.

Predictors

Patient demographics, comorbid conditions.

Outcome

First hospitalization for stroke, defined as a diagnosis at discharge (either primary or 1 of 4 secondary diagnoses) of ischemic or hemorrhagic stroke using International Classification of Diseases, Ninth Revision, Clinical Modification codes.

Results

HD and PD patients had higher incidences of hospitalized ischemic stroke (102.6 and 100.1/10,000 person-years) and hemorrhagic stroke (74.7 and 59.4/10,000 person-years) in comparison to the age- and sex-matched reference cohort (42.4 and 13.0/10,000 person-years, respectively). In addition to HD and PD therapy, older age, male sex, diabetes, and hypertension were found to be independent risk factors for both ischemic and hemorrhagic strokes. Using the HD group as the comparison group, we found that PD patients had a lower risk of hemorrhagic stroke (HR, 0.75; 95% CI, 0.58-0.96), and there was no significant difference in risks of ischemic stroke between PD and HD patients after adjusting for all potential confounders and competing risk of death, and matched by propensity scores.

Limitations

This was a retrospective study, and some important variables were not available.

Conclusions

Patients undergoing dialysis are at elevated risk of stroke. Patients undergoing PD appear to be less likely to develop hemorrhagic stroke than those undergoing HD. Comprehensive control of hypertension and diabetes is necessary when delivering dialysis treatment.

Section snippets

Data Source

This nationwide cohort study was based on data obtained from the National Health Insurance Research Database (NHIRD),10 which is abstracted from the reimbursement data of the National Health Insurance in Taiwan. The National Health Insurance program is a mandatory single-payer social health insurance launched on March 1, 1995, and 99.48% of citizens (23 million) were enrolled in the program by the end of 2008. This system covers most forms of treatment and the related expenses. Most

Baseline Characteristics

For January 1, 1998, to December 31, 2009, there were 73,630 (91.8%) incident HD patients and 4,364 (5.4%) incident PD patients; another 1,610 (2.0%) switched from PD to HD, and 562 (0.7%) switched from HD to PD. Because patients were grouped according to incident modality, overall, there were 74,192 HD patients and 5,974 PD patients included in this analysis. Within the same study period, 669,773 nondialysis patients were recruited into the reference cohort.

Before matching processes, mean ages

Discussion

To our knowledge, our study is the first nationwide population-based cohort study to quantify incidence rates of ischemic and hemorrhagic strokes in patients undergoing HD and PD in comparison to a reference cohort drawn from the general population. Although we found a 3-fold increased incidence rate in patients undergoing dialysis, it does not necessarily follow that such an increased risk is causally linked. However, we provide the following evidence to argue in support of such a hypothesis.

Acknowledgements

We are grateful to Jia-Ling Wu for providing statistical consulting services from the Biostatistics Consulting Center, National Cheng Kung University Hospital.

Support: This study was funded by a grant from E-Da Hospital, Kaohsiung, Taiwan (EDAHP 101024).

Financial Disclosure: The authors declare that they have no other relevant financial interests.

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