medwireNews: Results from an Australian study show that bipolar I disorder (BD I) is associated with higher costs than bipolar II disorder (BD II) or unipolar depression.

The team found that the combined indirect and direct financial impact of BD I is greater than that of BD II or unipolar depression.

"These findings are inconsistent with past research suggesting that BP I and BP II conditions are equally costly illnesses, instead finding significant cost differences across a variety of parameters," comment Gordon Parker (University of New South Wales, Sydney, Australia) and colleagues.

The findings come from a study of 44 patients with BD I, 102 with BD II, and 279 with unipolar depression attending a tertiary referral clinic in Sydney. The groups were similar in terms of illness duration, at around 20 years, and treatment history duration.

Indirect employment-related costs, such as those resulting from being absent from work due to illness, and direct costs, such as those resulting from medication, therapy, imaging, and hospitalization, were calculated using a variety of measures.

The researchers found that the mean indirect cost associated with BD I was AUS$ 134,318 (US$ 139,100, € 108,550) per year of illness, compared with $ 76,821 (US$ 79,557, € 62,082) for BP II and $ 68,347 (US$ 70,784, € 55,216) for unipolar depression.

The mean yearly direct costs associated with BD I, BD II, and unipolar depression were $ 26,353 (US$ 27,282, € 21,280), $ 17,579 (US$ 18,200, € 14,195), and $ 27,237 (US$ 28,199, € 21,994), respectively.

The combined indirect and direct costs were significantly higher in BD I than BD II or unipolar depression patients, while combined costs in BD II and unipolar depression patients were comparable.

The higher costs in BD I patients, compared with the other groups, were mainly due to a higher prevalence of government benefits, more time off work, and longer periods of time spent in hospital.

Parker and team summarize in the Journal of Affective Disorders: "Findings indicate that BD I illness generates more direct and indirect costs than BD II illness, while the latter was generally comparable with unipolar depression in terms of the lifetime cost."

They add: "Our findings could assist with priority-setting and lead to further investigation into the efficacy of particular treatments and interventions."

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