Like almost any intervention in the NICU (even maternal breast milk requires pumps and equipment, and kangaroo care requires chairs) there is some cost associated with routine probiotic administration. A new publication attempts to calculate the cost-effectiveness relationship. (Craighead AF, et al. Cost-effectiveness of probiotics for necrotizing enterocolitis prevention in very low birth weight infants. J Perinatol. 2020).

They used baseline estimates of NEC incidence of 5.8%, reduced to 2.4% by probiotics, costs of NEC hospitalisations and rates of serious long term outcomes and their costs from the literature. The baseline cost of the probiotics they included was $2,200 per baby.

Using these estimates, routine use of probiotics in at-risk babies (with that baseline NEC risk) cost $1,868 per QALY (quality-adjusted life-year) saved. Which is probably the most cost-effective intervention ever seen in an ICU!

When you perform a study like this you start with baseline assumptions and then see how variations of those assumptions affect the calculations.

If your region has more NEC than 5.8% then the costs per QALY are even lower. In fact, they showed that at a NEC incidence above 6.5% probiotics don’t cost anything, they start to have a negative cost, the the system as a whole saves money by instituting routine probiotics.

Even at a NEC incidence of 2% probiotics only cost about $18,000 per QALY, which is dramatically below the threshold used to fund new interventions in the UK (about $100,000).

If your probiotics cost less than $2200 per baby then again the calculations are changed. Our probiotics currently cost 50 cents a day per baby (single-use sachets of Florababy). I haven’t calculated the average cost per baby, but a 24-week infant receives them for 10 weeks, or $35. If you don’t change any other assumptions then the total cost per QALY is -$5000! At that low a cost, probiotics are cost-effective at a NEC incidence of 0.1% (a figure I just made up, the real threshold may be much lower than that).

The results of this analysis are hardly a surprise, probiotics are currently relatively inexpensive to use in the NICU and prevent a serious condition, here’s hoping that they stay that way.