COST-EFFECTIVENESS OF THE 4 PILLARS IMMUNIZATION TOOLKIT TO INCREASE VACCINATION RATES IN ADULT ELDERS

Purpose:

Despite many efforts, vaccination rates of US adults aged 65 years and older remain stalled at levels below national goals. The 4 Pillars Immunization Toolkit to improve adult vaccination rates was tested in a cluster randomized trial in 2 US cities; here we estimate the cost-effectiveness of this intervention in persons aged ≥65 years.

Method:

The 4 Pillars intervention includes immunization standing orders, vaccination access improvements, tracking tools, and a practice immunization champion (each chosen by individual physician practices) to improve vaccination rates. This intervention was compared to control among diverse populations and practices in Pittsburgh and Houston. In ≥65-year-old adults, these vaccines were targeted: influenza, the pneumococcal vaccines (polysaccharide and conjugate) and Tdap (tetanus, diphtheria, acellular pertussis). A decision tree model was used to estimate intervention cost-effectiveness. Trial data was used for vaccination rates and intervention implementation/maintenance costs. Vaccine effectiveness, illness rates, costs with/without vaccination, and utilities were obtained from US databases and literature data. Future costs and effectiveness were discounted 3%/year over a 10-year time horizon.

Result:

The 4 Pillars intervention, costing $1.78 per eligible patient per year, had per person total vaccination and illness costs that were $1.60 greater than no intervention while gaining 0.0031 QALYs, or $512/QALY gained. In 1-way sensitivity analyses, the intervention cost >$10,000/QALY gained if program-related absolute influenza vaccination rates increased <0.9% (base case 5%) or influenza vaccination effectiveness was <25.1% (base 59%). Results were insensitive to plausible individual variation of all other parameters, including absolute improvement in the vaccination rates against pneumococcal disease (base 10%, range 0-15%) or pertussis (10%, range 0-26%); no parameter variations caused the intervention to cost >$20,000 QALY gained. In a probabilistic sensitivity analysis, the 4 Pillars intervention was cost saving in 35.4% of model iterations and favored in 98.6% at a $50,000/QALY threshold.

Conclusion:

In an analysis largely based on clinical trial data, the 4 Pillars Immunization Toolkit was an economically reasonable intervention for improving vaccination rates in US seniors, with results robust to variation in sensitivity analyses.