Idiopathic short stature
Encyclopedia : I : ID : IDI : Idiopathic short stature
Idiopathic short stature (ISS) refers to extreme short stature that does not have a diagnostic explanation (idiopathic designates a condition that is unexplained or not understood) after an ordinary growth evaluation. The term has been in use since the 1980s or earlier without a precise percentile or statistical definition of "extreme,"
Definition
In 2003 Eli Lilly and Company offered a more precise defintion of ISS when the pharmaceutical company submitted clinical trial data to the U.S. Food and Drug Administration (FDA) requesting approval to advertise their brand of growth hormone for the treatment of ISS. They proposed a definition of a height more than 2.25 standard deviations below mean, roughly equal to the shortest 1.2% of the population.Controversies
Since 2003 this diagnosis has become controversial.- Does it make sense to define a disease solely as a certain percentage of the population if there is little perceptible difference between a person just above the cutoff and another person just below the cutoff?
- How many of the people in the lowest 2% of the population are not simply "idiopathic" but rather have subtler disorders of growth hormone or IGF1 production or responsiveness or any of hundreds of other known or unknown conditions not readily detected by an "ordinary" growth evaluation?
- Should insurance or government (the other 99% of the population) pay US$100,000 or more to treat someone to move them from the first percentile to perhaps the 10th? Would that just transfer the disadvantages to those in what was previously the "2nd" percentile?
- Even if treatment successfully changes height to the 5th or 10th percentile, does it actually improve the person's life in any measurable way?
See also
References
- Leschek EW, Rose SR, Yanovski JA, Troendle JF, Quigley CA, Chipman JJ, Crowe BJ, Ross JL, Cassorla FG, Blum WF, Cutler GB, Baron J. Effect of growth hormone treatment on adult height in peripubertal children with idiopathic short stature: a randomized, double-blind, placebo-controlled trial. J Clin Endocrinol Metab 89:3140-8, 2004. This is the formal publication of the trial submitted to support FDA approval.
- Lee, Joyce M. MD; Matthew M. Davis, MD, MAPP; Sarah J. Clark, MPH; Timothy P. Hofer, MD; Alex R. Kemper, MD, MPH, MS. Estimated Cost-effectiveness of Growth Hormone Therapy for Idiopathic Short Stature. Arch Pediatr Adolesc Med. 2006;160:263-269. Cost-effectiveness analysis of GH therapy for ISS .
External links
- [Account of the FDA approval of Humatrope for ISS]
- [Excellent synopsis of GH use for ISS from the Minnesota Dept of Health]
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