Prevalence estimation of essential tremor in Hungary between 2010 and 2020 based on the National Health Insurance Fund Database

Abstract

The published prevalence of essential tremor is variable worldwide and lacking in Central Europe. We aimed to estimate its prevalence in Hungary and to explore the locally applied therapeutic approaches. We collected data from the National Health Insurance Fund database and pharmacy database registered between 2010 and 2020. Matching the specified codes of the International Classification of Diseases and the individually tailored combination of interventions, we attempted to exclude Parkinson's disease and other tremor evoking conditions. We estimated the period prevalence of essential tremor age standardized to the European Standard Population at 378-388/100,000. After excluding patients with possible Parkinsonian syndromes, we found that 36.4% of patients with tremor did not take any medication during the study period. Most of the rest used alprazolam followed by propranolol for the longest period of time; the alprazolam and propranolol combination was the most preferred. Deep brain stimulation and ablative surgery were chosen for less than 0.5% of the patients. Our strict methods probably underestimate the essential tremor prevalence in Hungary, which, however, does not differ considerably from international results. Given the limitations of medication therapy, expanding and improving neurosurgical interventions may help improve the quality of life of patients with essential tremor.

Keywords: Epidemiology; Essential tremor; Hungary; Prevalence; Therapy; Tremor.

Fig. 1

Flowchart of the selection process. The flowchart diagram shows the steps of selection from our initial database to the final established number of patients with essential tremor. We excluded the patients represented in the colored boxes from the study. Patients represented in the black box had no pharmacy records (Group 3); in the gray box, they had less than two years of follow-up time (Group 5). Patients depicted in the blue box were considered to have Parkinson’s disease/syndrome (Group 7). The remaining Not Parkinsonian Tremor Group contained data from 40,712 patients (Group 6). After ruling out people with possible Essential tremor plus syndromes and other tremor-eliciting conditions and treatments (Group 9), the estimated number of patients with essential tremor was 37,249 (Group 8).

Fig. 2

Customs of medication refills in the Not Parkinsonian Tremor Group (Group 6). During our investigation period, 14,825 patients did not try any studied medication. Most of those being on pharmacotherapy picked up the prescription of alprazolam one or more times. The ratio of those who refilled the respective medication more than once compared to those who asked for it only once at the pharmacy, as a metric of adherence, was the highest for alprazolam. Only 138 patients used topiramate.

Fig. 3

The number of patients in Group 6 using the represented antitremor drug for the most extended period of time. Each column represents the number of patients who refilled a particular medication most prolongedly out of the five studied ones during our observation period. Most patients opted for alprazolam for the most extended period of time.

Fig. 4

The lengths of the medication use in Group 6. The plot shows the time period in months when the patients refilled the listed drugs from the pharmacy. The duration of medication uses significantly differed (p < 0.0001, Kruskal-Wallis test), being the longest for alprazolam and the shortest for topiramate. Post hoc Dunn’s test showed that the difference was significant between each medication (p < 0.05), except for the comparison between propranolol and primidone (p > 0.05; NS).