Nationwide Analysis of Changes in Medical Utilization Before and After a New Panic Disorder Diagnosis

Objective Panic disorder (PD) is associated with somatization and high medical utilization in primary care settings. Treatment of PD could reduce the frequency of panic attacks and visits to emergency departments, but the associated change in medical utilization is unknown. This study investigated the change in medical utilization before and after a PD diagnosis. Method This study identified 8722 patients with PD enrolled in the National Health Insurance Research Database in Taiwan between January 1, 2000, and December 31, 2012. We used a case-crossover study design to compare medical utilizations with a 1-year time window before and after new PD diagnoses, including medical examinations, specialty visits, and medication used. A conditional logistic regression model was used to estimate changes in comorbidity before and after new PD diagnoses. Results The utilization of examinations-including electrocardiography, radiography, and sonography-decreased within 1 year after PD diagnosis compared with 1 year before PD diagnosis. Outpatient and emergency department visits to nonpsychiatric departments decreased (risk ratio [RR] = 0.989 [95% confidence interval {CI} = 0.985-0.993] and RR = 0.924 [95% CI = 0.894-0.956], respectively), whereas outpatient visits to psychiatric departments increased (RR = 1.193, 95% CI = 1.171-1.215). PD diagnosis is associated with increased use of antidepressants (RR = 12.65) and benzodiazepines (RR = 11.63), an increased ratio of comorbid depressive disorder (RR = 3.06) and bipolar disorder (RR = 1.77), and a decreased ratio of nonpanic anxiety disorder (RR = 0.69). Conclusions New PD diagnoses are associated with decreased laboratory examination and nonpsychiatric service utilization, along with increased psychiatric service utilization. We suggest that PD should be detected earlier for mitigating potentially unnecessary use of nonpsychiatric examinations and services.