Prevalence of Hypophosphatemic Rickets in Colombia: A Prevalence-Estimation Model in Rare Diseases. 2018

Abstract

Background: Hypophosphatemic rickets is a rare, genetic syndrome with multisystem involvement. It causes skeletal abnormalities, painful enthesopathies, increased risk of fracture, and short stature; and generates a substantial burden of disease, disability, and worsening of quality of life. To improve health conditions and quality of life of people living with this disease, it is essential to know its prevalence –which is currently unknown in Colombia. This study aimed to estimate the prevalence of hypophosphatemic rickets in Colombia by using a mathematical model and national statistics. Methods: We executed a model to estimate probabilities of transitions between health, disease, and death states (Markov chains). The model was fed with international prevalences taken from original studies (systematic review), administrative records’ data from SISPRO (a national health information system) using the International Classification of Diseases (ICD)-10 E833 code, vital statistics, and census data. World Health Organization’s (WHO) DISMOD II software was used to develop the model. Findings: The estimated overall prevalence of hypophosphatemic rickets in Colombia in 2018 was 2·03 cases per 100 000 people (981 affected people), with a sensitive range of 1·97 to 2·09. The estimated prevalence by sex was 2·61 (645 people) and 1·43 (336 people) cases per 100 000 women and men, respectively. Interpretation: Our overall estimated prevalence shows consistency with original international data. As the first prevalence estimation of hypophosphatemic rickets in Colombia, it becomes relevant to support public health decisions for rare diseases and to provide a pre-test probability framework in clinical practice. DISMOD II is a useful tool to estimate the prevalence of rare and orphan diseases, when probabilistic studies cannot be carried out. There are limited bibliographic resources worldwide reporting prevalence values supported by original studies. Our study can be used as a reference in this regard, especially for Latin America. Funding: Ultragenyx Pharmaceutical, as a donation. Declaration of Interest: We declare no competing interests.