Vitamin D Insufficiency

Vitamin D hormone production declines markedly if 25-hydroxyvitamin D₂ and 25-hydroxyvitamin D₃ are in short supply, a condition often described by terms such as “vitamin D insufficiency” or, if more pronounced, “vitamin D deficiency”. Therefore, measurement of 25-hydroxyvitamin D levels in blood has become the accepted method among healthcare professionals to monitor vitamin D status.

Vitamin D insufficiency is nearly ubiquitous in the chronic kidney disease (CKD) population.  Recent studies have documented that the great majority of CKD patients have low blood levels of 25-hydroxyvitamin D, suggesting that the onset of CKD is a significant risk factor for vitamin D insufficiency and that the prevalence of vitamin D insufficiency increases as CKD progresses.  In addition, recent studies have linked vitamin D insufficiency to progression of CKD and increased morbidity and mortality in hemodialysis patients.¹

Market Opportunity

Vitamin D insufficiency has been shown to exacerbate the development of secondary hyperparathyroidism (SHPT) and related bone disease (renal osteodystrophy). Published sources indicate that 70% of Stage 3, 80% of Stage 4, and 90% of Stage 5 patients suffer from vitamin D insufficiency. There are currently over 7.7 million Stage 3 and 4 CKD patients, and over 472 000 Stage 5 patients in the U.S.²

Parallel advances in the understanding of vitamin D insufficiency and its complications have resulted in a new global initiative known as Kidney Disease: Improving Global Outcomes (KDIGO). The forthcoming new guidelines from KDIGO are expected to strongly advocate the treatment of vitamin D insufficiency in CKD patients with SHPT, along with the more widely accepted vitamin D replacement hormone therapy for SHPT in CKD patients.

Currently in the U.S., there are only two options available for the prevention and treatment of vitamin D insufficiency: Over-the-counter (OTC) dietary supplements which typically contain 400 to 5,000 IU per unit dose of either vitamin D₂ or D₃, and prescription oral products (Drisdol^® and generics) containing 50,000 IU per unit dose of vitamin D₂. Recent studies have shown that both therapies have limited efficacy in restoring adequate vitamin D prohormone levels.

1. Wolf et al. “Vitamin D levels and early mortality among incident hemodialysis patients”. Kidney International (2007) 72, 1004–1013;

2. NKF 2002 K/DOQI Clinical Practice Guidelines for Bone Metabolism and Disease in Chronic Kidney Disease, U.S. Renal Data System 2007 Annual Data Report.

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