Total drug treatment and comorbidity in myasthenia gravis: a population-based cohort study

Abstract

Background and purpose: Comorbidity in myasthenia gravis (MG) is important for diagnosis, treatment and prognosis. Disease complexity was assessed by examining total drug treatment, immune therapy and comorbidity in a complete national MG cohort.

Methods: All recipients of the MG-specific drug pyridostigmine 2004-2010 registered in the compulsory Norwegian Prescription Database who met the inclusion criteria were included. The pyridostigmine group was compared with the general Norwegian population.

Results: Myasthenia gravis patients received co-medication more often than the controls for nearly all groups of medication, including insulins (95% confidence interval 2.0-3.7), thyroid therapy (1.7-2.5), antidepressants (1.3-1.7), anti-infectives (1.2-1.4), lipid-modifying agents (1.1-1.4) and immunomodulating agents (6.8-8.8).

Conclusions: Myasthenia gravis patients are more often treated with non-MG prescription drugs than controls, reflecting frequent co-medication and comorbidity.

Keywords: comorbidity; drug therapy; myasthenia gravis.

Figure 1

Selection of the MG study cohort. *Recipients of pyridostigmine who did not meet the inclusion criteria during the study period.

Figure 2

(a) Mean number of new groups of immunomodulating agents used in MG patients (%) below and above 50 years of age after MG diagnosis per year, 2004–2010. Open bars, patients <50 years; hatched bars, patients ≥50 years. (b) Mean number of new groups of immunomodulating agents used in MG men and women (%) after MG diagnosis per year, 2004–2010. Open bars, men; hatched bars, women.