Resumen de Oral Health and Mortality in Patients With Chronic Kidney Disease
Hellevi Ruokonen, Karita Nylund, Jussi Furuholm, Jukka H. Meurman, Timo Sorsa, Karoliina Kotaniemi, Fernanda Ortiz, Anna Maria Heikkinen
Background: Factors related to mortality of patients with chronic kidney disease (CKD) were investigated to find out whether oral disease inflammatory burden or different etiology (diabetes nephropathy vs. other etiologies) of CKD could be associated with mortality.
Methods: This prospective cohort study comprised 144 adults at the predialysis stage. Clinical oral and radiologic examination was made from 2000 to 2005. Patients were followed up until August 2015 (complete follow-up time: 157 months). Cause of death could be verified from 62 of 65 patients. Clinical health data were combined with mortality records obtained from the Finland national statistics database. Number of teeth, total dental index (TDI), and periodontal inflammatory burden index were calculated to describe degree of oral inflammation.
Results: Primary causes of death were cardiovascular diseases, infection, and cancer. There was a statistically significant difference in survival between diabetic nephropathy (23.8%) and other patients with CKD (59.9%; log-rank test P <0.001). A Cox regression model showed fewer teeth, higher age, and diabetes mellitus were statistically significant independent risk factors for death. Deceased patients had fewer teeth (P <0.001) and higher TDI (P <0.05).
Conclusions: Risk of death was higher among patients with diabetic nephropathy. The deceased had fewer teeth and more oral infections. However, indices used failed to show independent association with survival.
Chronic kidney disease (CKD) is a worldwide problem with adverse outcomes such as cardiovascular disease and premature death.1 Diabetes mellitus (DM) is the most common cause of CKD.2 Other etiologies are: 1) hypertension; 2) glomerulonephritis; 3) systemic autoimmune diseases; 4) atherosclerotic renovascular disease; 5) polycystic kidney disease; 6) obstructive uropathy; and 7) chronic pyelonephritis.3,4 According to the World Health Organization (WHO) >422 million people worldwide have diabetes and the number is increasing.5 In Finland, where this study was conducted, diabetic nephropathy is the leading cause of end-stage renal disease (ESRD),6 followed by glomerulonephritis, polycystic kidney disease, and nephrosclerosis.7 A detailed report provided by the European Dialysis and Transplant Association Registry revealed patient survival after 5 years of dialysis treatment is 52%, whereas after receiving a kidney transplant 91% of patients are alive 5 years later.8 CKD patients have an increased risk of atherosclerosis complications.1 Cardiovascular disease is the leading cause of death among patients with CKD.9 Previous studies show patients with CKD and DM have more decayed teeth, lower stimulated salivary flow rates, and deep periodontal pockets more often than other patients with CKD, rendering patients liable to oral infections.10,11 Poor oral health may contribute to increased mortality in patients with CKD because of chronic low-level systemic inflammation caused by oral and dental infections.12 Periodontitis is a chronic inflammatory disease caused by interplay between Gram-negative periodontal pathogen activity and a subsequent host response.13 Periodontitis affects approximately half the adult population worldwide and, together with dental decay, is the main cause of tooth loss in middle-aged and older people.14,15 Missing teeth, in turn, have been associated with the risk of atherosclerotic vascular disease16 and may be used as proxy in predicting incident cardiovascular events, DM, and death.17 Considering this background, the aim of the present study is to examine cause of death in patients enrolled in a previous study conducted by the authors.10 Clinical oral examinations were conducted at the predialysis stage of patients with CKD who have, since then, been followed up. Originally, patients with diabetic nephropathy had a higher oral inflammatory burden at predialysis stage than other patients with CKD.11 An emphasis of the study is to clarify if there is an association between total oral inflammatory burden and mortality among the study patients. It was hypothesized that this might be the case. It was also expected that patients with diabetic nephropathy would have higher mortality compared with patients with other renal disease etiologies.
