Abstracts

Rationale: Tuberous sclerosis complex (TSC) is a rare disease characterized by benign tumor growth, primarily in the brain, eyes, heart, kidney, lungs, and skin, which may result in neurological and systemic manifestations including seizures, neurocognitive deficits, renal disease, and pulmonary disease. With incidence rates of 1-2 per 6,000 live births, TSC is thought to be under-diagnosed. Understanding conditions and clinical events that occur prior to diagnosis may help to reduce delays in diagnosis as well as improve rates of diagnosis. This study assessed timing of TSC diagnosis for related conditions, and examined the earliest TSC-related conditions to precede diagnosis of TSC. Methods: This retrospective study used medical and pharmacy claims and enrollment data from 2 large US national health plan databases of commercial and Medicare Advantage enrollees. Included TSC subjects (ICD-9-CM 759.5x) were identified between Jan 2000-Dec 2011; index dates were assigned as the date of first TSC diagnosis. Patients were required to have a minimum of 12 months pre-index health plan enrollment (minimum 6 months for patients aged 2 years or younger), and 12 months post-index enrollment. All available baseline data (as far back as 1993) were used to identify clinical conditions, events, procedures, and health care visits prior to the initial TSC diagnosis; these conditions were also identified over the follow-up period. Descriptive analyses and survival models were estimated. Results: Among the 2,163 patients who were diagnosed with TSC, only one-third were aged less than 30 years, reflecting the inclusion of Medicare Advantage patients in the analysis. Diagnoses of seizures prior to TSC diagnosis were a common occurrence and were significantly more common among the younger age groups, starting at 27% for patients aged 0-4, 22% (age 5-9), 14% (age 10-4), 14% (age 15-19), 13% (age 20-24), and < 6% for all older age groups. Seizures post-TSC diagnosis started at a high of 38% of patients aged 0-4 having any seizure disorder, and gradually decreasing to zero among the oldest age-group. Further, patients showed evidence of being treated for TSC-related conditions an average of 2.6 years earlier than their actual diagnosis with TSC, with treatment preceding diagnosis ranging from an average of 1.4 years earlier for patients aged 4 or younger, to 4.7 years earlier for patients aged 80 or older. Skin conditions were also common prior to TSC diagnoses, experienced by 12% of patients. Conditions associated with a diagnosis of TSC included seizures, skin conditions, bone cysts, anxiety, and ADHD. Conclusions: Seizures were a condition commonly experienced by patients prior to diagnosis of TSC; understanding the initial diagnoses experienced by TSC patients may help lead to earlier diagnosis and treatment of TSC. Funding: Funding for this study was provided to Optum by Novartis Pharmaceuticals Corporation.