OBJECTIVES: Some of the common diseases are the comorbidities of rare diseases. Requirements for the billing codes in the documentation of health care providers and payer (NHF) underestimate the prevalence rate of rare diseases and their complications. We examined the economic burden of rare disease (tuberous sclerosis - TSC) in Poland and its comorbidities (epilepsy and status epilepticus) taking into account sensitivity analysis.

METHODS: To estimate the direct medical costs of disorders and for TSC disorder the costs of its complications, data from the NHF were used with related etiological fraction calculus and sensitivity analysis. They include the costs of outpatient consultation, hospitalization, rehabilitation, and drugs. Indirect costs embraced costs of lost productivity due to absenteeism and inability to work (handicap) caused by these diseases, and costs of lost productivity due to the premature mortality. They were calculated upon Social Insurance Institution and Central Statistical Office datasets using human capital method.

RESULTS: The total cost of epilepsy and status epilepticus in Poland amount to EUR 260.8 million. The total cost of TSC amount to EUR 571.3 thousand, of which 66% is the cost of lost productivity (indirect), and 34% is the cost of health-care services (direct). Analysis of costs of TSC and their complications indicates that costs of disease-related complications are much higher than disease itself (TSC: EUR 571.3 thousand; TSC complications: EUR 1.5 million- EUR 2.7 million, taking into account sensitivity analysis).

CONCLUSIONS: Total cost of TSC and its complications amounts to: EUR 2.1 million-EUR 3.3 million in Poland. The results of this study show that costs of treatment of patients with complications are higher than those related to the patient with well-controlled diseases. Moreover higher costs of common diseases results from insufficient financing of rare diseases which in many cases have the common diseases as the comorbidity (e.g. TSC and epilepsy).