Background Systemic sclerosis (SSc) can affect multiple organ systems including the kidney. Renal disease, especially chronic kidney disease (CKD), remains an important cause of morbidity and mortality in SSc. The spectrum of renal complications in SSc include scleroderma renal crisis (SRC), normotensive renal crisis, antineutrophil cytoplasmic antibody associated glomerulonephritis, penicillamine-associated renal disease, and reduced renal functional reserves. Furthermore, subclinical renal impairment affects approximately 10-55% of SSc patients and might be associated with other vascular manifestations. However, the available evidence on CKD in patients with SSc residing in low-middle income countries (LMIC) is scarce. Because the health system of LMIC, and especially Peru, could have great differences in access to diagnosis and management of SSc, it is important to identify which clinical factors would be associated with CKD in patients with this autoimmune disease.
Objectives To identify the associated factors to renal involvement in Peruvian patients with SSc.
Methods We analyzed the associated factors to renal involvement in SSc patients at Hospital Nacional Edgardo Rebagliati Martins Lima-Peru, a national reference hospital in Peru. Between June 2001 and December 2018, we included ambulatory patients, older than 18-year-old with SSc that met the ACR-EULAR classification criteria. In patients who accepted to get informed consent, a complete clinical assessment and a sociodemographic survey were done. Additional clinical data were collected from their clinical records. Multiple Poisson regression with robust standard errors was used to identify significant and independently associated factor. Two models were estimated: one based on theoretically selected variables and another parsimonious model based on variables that was selected using a manual backward selection procedure with a predetermined alpha of 0.2. Adjusted prevalence ratio (aPR), 95% confidence interval and p-values were reported.
Results One hundred and five patients with SSc were included in this study, 15.1% had chronic kidney disease. The average age was 57.8 years; 92% were women, and the average time of illness was 8.2 years. The model based on theory showed that age (aPR = 1.03, 95% CI = 0.99-1.07, p = 0.143) and exposure to Penicillamine (aPR = 0.51, CI 95% = 0.19-1.33, p = 0.170) were marginally associated (p <0.2) with CKD, while pulmonary hypertension (aPR = 2.76, 95% CI = 1.29-5.89, p = 0.009) and arterial hypertension (aPR = 3.51, 95% CI = 1.06-11.6, p = 0.04) were significantly associated (<0.05) with CKD. The parsimonious model retained pulmonary hypertension (aPR = 3.74, 95% CI = 1.67-8.36, p = 0.001) and arterial hypertension (aPR = 7.45, 95% CI = 3.31-16.7, p <0.001) as significantly associated factors to CKD.
Conclusion Hypertension, a classic cardiovascular risk factor, and pulmonary hypertension were important factors associated with CKD. The appropriate management of these factors must be taken into account to prevent CKD. Prospective cohort studies should evaluate the influence of these factors in reducing the incidence of CKD.
References  S.I. Nihtyanova VHOCPD. Current management strategies for systemic sclerosis. Clin Exp Rheumatol. 2014; 32(81: 156-154).
 Rosato E, Gigante A, Barbano B, Gasperini ML, Cianci R, Muscaritoli MPrognostic Factors of Renal Involvement in Systemic Sclerosis. Kidney Blood Press Res. 2018;43(3):682-689
Disclosure of Interests None declared
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