Table 1.

Parameters in the simulation

Parameter in simulation	Value
Size of cohort	2000 subjects
Duration of follow-up	5 years
Proportion of subjects with CD4 <200 cells/ml	30%
Proportion of subjects virologically suppressed
CD4 <200 cells/ml	50%
CD4 ⩾200 cells/ml	80%
Probability of TMP-SMX prescription if CD4 <200 cells/ml	80%
Probability of TMP-SMX adherence
HIV viral load <1000 copies/ml	100%
HIV viral load ⩾1000 copies/ml	25%
Baseline risk of SSTI	0·000125/day
Hazard ratio of SSTI*
CD4 <200 cells/ml (immunological effect)	3
HIV viral load <1000 copies/ml	0·5
TMP-SMX use	0·7

TMP-SMX, Trimethoprim-sulfamethoxazole; SSTI, skin and soft tissue infection.

^*This is the independent multiplicative increase in risk associated with each factor. That is to say, those with CD4 count <200 cell/ml experience a risk of SSTI which is triple that observed in subjects with a higher CD4 count, subjects with HIV viral load <1000 copies/ml experience a risk of SSTI which is half that seen in subjects with higher viral loads, and TMP-SMX users experience a risk of SSTI which is 0·7-fold that seen in subjects not using TMP-SMX.