Introduction and objectives: Occult renal disease (ORD) is a condition that characterizes the early stages of renal failure and which cannot be detected by routine monitoring. The aims of this study were to determine the prevalence of ORD in hypertensive patients attending cardiology outpatient clinics and to identify its relationship with specific cardiovascular risk factors or treatment.
Methods: A cross-sectional, retrospective, multicenter observational study was carried out in 1214 hypertensive patients attending cardiology outpatient clinics.
Results: Data from 1190 patients (98%) were analyzed. In 11%, the glomerular filtration rate (GFR) was calculated by the attending cardiologist using the Modification of Diet in Renal Disease equation. Overall, 9.5% of patients were found to have ORD. Affected patients were more likely to be female, to be older, to have a history of dyslipidemia, diabetes, a sedentary lifestyle or atrial fibrillation or a long history of hypertension compared with those without ORD, but were less likely to have a history of dyslipidemia, diabetes or a sedentary lifestyle than those with renal failure. There was no significant difference in treatment. Moreover, ORD was observed in 2.9% (two of 68) of those aged under 50 years, in 3.3% (seven of 210) aged 50-60 years, in 9.3% (37 out of 398) aged 60-70 years and in 13.5% (70 out of 518) aged over 70 years.
Conclusions: Almost 10% of hypertensive patients reviewed by a cardiologist had moderate renal dysfunction that had not been investigated. They represent an unrecognized population with an intermediate cardiovascular risk. Consequently, it is recommended that the GFR should be calculated, especially in women and older patients.