Hypophosphatemic Osteomalacia Associated with Adefovir-induced Fanconi Syndrome Initially Diagnosed as Diabetic Kidney Disease and Vitamin D Deficiency

Abstract

A 68-year-old man with type 2 diabetes mellitus and chronic hepatitis B infection was referred to the nephrology department before planned surgery for hepatocellular carcinoma. He had been receiving low-dose adefovir dipivoxil (ADV) for 11 years. Laboratory findings revealed impaired re-absorption in the proximal renal tubules. He had been diagnosed with diabetic kidney disease and osteomalacia due to vitamin D deficiency; thus, ADV was not discontinued until he was referred to us. In this case, concomitant diabetes mellitus and vitamin D deficiency might have prevented the early diagnosis of ADV-induced Fanconi syndrome.

Multidisciplinary patient care in X‐linked hypophosphatemic rickets: one challenge, many perspectives

“…A case of TIO due to meningioma and effective burosumab treatment was published recently [28]. Moreover, several drugs such as adefovir or intravenous iron therapy can lead to hypophosphatemia and similar symptoms to XLH [29,30]. Therefore, TIO, drug-induced hypophosphatemia and other forms of osteomalacia and renal tubular phosphate wasting must also be considered in adult patients with low phosphate levels.…”

Fanconi syndrome induced by adefovir dipivoxil: a case report and clinical review

“…However, several recent studies reported low FGF23 levels in patients with ADV-induced FS, suggesting the FGF23 may not cause hypophosphatemia in patients with drug-induced FS 33 and it may not be involved in the development of HO induced by ADV. 34…”

“…The main characteristics of 32 patients with ADV-induced FS, including eight patients in our institution and 24 published cases, are summarized in Table 4 . 5 , 18 , 22 , 23 , 36 – 43 …”

“… 52 However, some recent studies indicated that renal damage induced by ADV may be irreversible. 18 , 23 , 29 , 34 However, it may be not sufficient to evaluate renal function using only β2-M. 18 Thus, further comprehensive research using longer treatment periods and considering eGFR, β2-M, RBP, and other potential biomarkers is needed to clarify whether renal dysfunction induced by ADV is completely recoverable. Moreover, a study using a 6‐month follow‐up period found that patients with chronic kidney disease and tubule acidosis have a poor prognosis.…”