Survival Analysis and Causes of Death of Patients with Lupus Nephritis

Abstract

Introduction: Lupus nephritis (LN), which is an important clinical finding of systemic lupus erythematosus (SLE), may lead to death if not treated. Contrary to the case in developed countries, the causes of mortality and survival rates associated with LN have not been adequately analyzed in developing countries. For this reason, in our study, we aimed to investigate the causes of mortality, 5-year and 10-year survival rates, and standardized mortality ratios (SMR) of patients with LN. Material&Method: 73 patients that applied to XXX University XXX Hospital Rheumatology Outpatient Clinic during the period of 2010 to 2020 and who were diagnosed with LN as substantiated by biopsy were included in the study. Age, gender, diagnosis, treatment, laboratory and pathology data of these patients were retrospectively scanned and recorded. SLEDAI (Systemic Lupus Erythematosus Disease Activity Index) and ACR (American College of Rheumatology) Damage Index of the patients were calculated. Statistical analyses were performed using the SPSS V21.0 (SPSS Inc., Chicago, IL) software. Cumulative survival curves were created using the Kaplan-Meier method. Multivariate Cox regression analysis was used to determine the independent factors affecting survival. Results: A total of 73 SLE patients, 63 (86.3%) of whom were female and 10 (13.7%) of whom were male, were included in our study. The most prevalent clinical criteria detected in these patients were proteinuria, which was detected in 73 (100%) patients, arthritis, which was detected in 56 (76.7%) patients, and photosensitivity, which was detected in 49 (67.1%) patients. The mean disease duration of the patients was calculated as 138.1 ± 126.4/month. Death occurred in 4 (3 male, 1 female) patients (5.5%) out of the 73 patients during the course of the disease. The 5-year survival rate of the patients was calculated as 95.7%, whereas the 10-year survival rate of the patients was calculated as 94.0%. Cox regression analysis revealed that the prognosis of the disease was significantly more mortal in male patients compared to the female patients [p = 0.01, HR (Hazard Ratio) = 19.248], and in patients with pericarditis compared to the patients without pericarditis (p = 0.02, HR = 9.822). On the other hand, SMR was determined as 5.52 in SLE patients with LN, which indicates a higher SMR compared to the general population. Conclusion: Our study is the first LN mortality series study in Turkey. The mortality rates determined in our study were found to be comparable to the mortality rates reported in the literature. Male gender and pericarditis were determined as the risk factors associated with LN in terms of mortality. Hence, male LN patients and LN patients with pericarditis should be followed up more closely.

Keywords

• Systemic lupus erythematosus
• Lupus nephritis
• Mortality

References

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