Costs for patients in whom drugs were permanently discontinued because of suspected adverse events (all costs in Canadian $)
| n | Costs for scheduled care | Costs for non-scheduled care | Total costs | Average cost per patient | p Value* | |
| Treatment regimen | ||||||
| 4RIF | 28 | $9667 | $12232 | $21899 | $782 | 0.05 |
| 9INH | 41 | $15013 | $24651 | $39664 | $967 | |
| Type of adverse event | ||||||
| Hepatotoxicity | 28 | $11063 | $20942 | $32005 | $1143 | <0.001 |
| Haematological | 4 | $1271 | $2694 | $3965 | $991 | |
| Rash | 17 | $5219 | $6230 | $11449 | $673 | |
| Gastrointestinal intolerance | 7 | $1543 | $2269 | $3812 | $545 | |
| Drug interaction | 1 | $305 | $911 | $1216 | $1216 | |
| Other‡ | 12 | $5280 | $3837 | $9117 | $760 | |
| Final designation† | ||||||
| Grade 3–4 drug-related adverse event | 24 | $9317 | $18668 | $27985 | $1166 | <0.001 |
| Grade 1–2 drug-related adverse event | 16 | $4493 | $5850 | $10343 | $646 | |
| Not a drug-related adverse event | 29 | $10870 | $12364 | $23234 | $801 | |
| All patients in whom drugs were stopped | 69 | $24680 | $36883 | $61563 | $892 | – |
↵* p Value from one-way ANOVA for comparison of mean costs within subgroups.
↵† Final designation regarding severity and relationship to study drug were made by an independent panel, blinded to study drug.
↵‡ Other reasons for referral to independent review panel were: pregnancy (n=5 of whom 1 later completed therapy), arthralgia (n=1), rheumatoid arthritis (n=1), fatigue (n=1), decreased libido (n=1), dengue fever (n=1), depression (n=1) and death (n=1). None of these was judged to be related to the study drug.
9INH, isoniazid treatment for 9 months; 4RIF, rifampin treatment for 4 months.