Cost-effectiveness of a cervical screening program with human papillomavirus vaccine

Can cost-effectiveness results be combined into a coherent league table? Case study from one high-income country

Background

Doubts exist around the value of compiling league tables for cost-effectiveness results for health interventions, primarily due to methods differences. We aimed to determine if a reasonably coherent league table could be compiled using published studies for one high-income country: New Zealand (NZ).

Methods

Literature searches were conducted to identify NZ-relevant studies published in the peer-reviewed journal literature between 1 January 2010 and 8 October 2017. Only studies with the following metrics were included: cost per quality-adjusted life-year or disability-adjusted life-year or life-year (QALY/DALY/LY). Key study features were abstracted and a summary league table produced which classified the studies in terms of cost-effectiveness.

Results

A total of 21 cost-effectiveness studies which met the inclusion criteria were identified. There were some large methodological differences between the studies, particularly in the time horizon (1 year to lifetime) but also discount rates (range 0 to 10%). Nevertheless, we were able to group the incremental cost-effectiveness ratios (ICERs) into general categories of being reported as cost-saving (19%), cost-effective (71%), and not cost-effective (10%). The median ICER (adjusted to 2017 NZ$) was ~ $5000 per QALY/DALY/LY (~US$3500). However, for some interventions, there is high uncertainty around the intervention effectiveness and declining adherence over time.

Conclusions

It seemed possible to produce a reasonably coherent league table for the ICER values from different studies (within broad groupings) in this high-income country. Most interventions were cost-effective and a fifth were cost-saving. Nevertheless, study methodologies did vary widely and researchers need to pay more attention to using standardised methods that allow their results to be included in future league tables.

Electronic supplementary material

The online version of this article (10.1186/s12963-019-0192-x) contains supplementary material, which is available to authorized users.

Simple but not simpler: a systematic review of Markov models for economic evaluation of cervical cancer screening

The aim of this study was to critically evaluate the quality of the models used in economic evaluations of screening strategies for cervical cancer prevention. We systematically searched multiple databases, selecting model-based full economic evaluations (cost-effectiveness analyses, cost-utility analyses, and cost-benefit analyses) of cervical cancer screening strategies. Two independent reviewers screened articles for relevance and performed data extraction. Methodological assessment of the quality of the models utilized formal checklists, and a qualitative narrative synthesis was performed. Thirty-eight articles were reviewed. The majority of the studies were conducted in high-income countries (82%, n=31). The Pap test was the most used screening strategy investigated, which was present in 86% (n=33) of the studies. Half of the studies (n=19) used a previously published Markov model. The deterministic sensitivity analysis was performed in 92% (n=35) of the studies. The mean number of properly reported checklist items was 9 out of the maximum possible 18. Items that were better reported included the statement of decision problem, the description of the strategies/comparators, the statement of time horizon, and information regarding the disease states. Compliance with some items of the checklist was poor. The Markov models for economic evaluation of screening strategies for cervical cancer varied in quality. The following points require improvement: 1) assessment of methodological, structural, heterogeneity, and parameter uncertainties; 2) model type and cycle length justification; 3) methods to account for heterogeneity; and 4) report of consistency evaluation (through calibration and validation methods).

Cost-effectiveness and equity impacts of three HPV vaccination programmes for school-aged girls in New Zealand

BACKGROUND

As with many high-income countries, vaccination coverage against human papilloma virus (HPV) infection is not high in New Zealand (NZ) at 47% in school-aged girls for three doses. We estimate the health gains, net-cost and cost-effectiveness of the currently implemented HPV national vaccination programme of vaccination dispersed across schools and primary care, and two alternatives: school-based only (assumed coverage as per Australia: 73%), and mandatory school-based vaccination but with opt-out permitted (coverage 93%). We also generate estimates by social group (sex, ethnic and deprivation group).

METHODS

A Markov macro-simulation model was developed for 12-year-old girls and boys in 2011, with future health states of: cervical cancer, pre-cancer (CIN I-III), genital warts, and three other HPV-related cancers (oropharyngeal, anal, vulvar cancer). In each state health sector costs, including additional health sector costs from extra life, and quality-adjusted life years (QALYs) were accumulated.

RESULTS

The current HPV vaccination programme has an estimated cost-effectiveness of NZ$18,800/QALY gained (about US$9700/QALY gained using the OECD's purchasing power parities; 95% UI: US$6900 to $33,700) compared to the status quo in NZ prior to 2008 (no vaccination, screening alone). The incremental cost-effectiveness ratio (ICER) of an intensive school-based only programme of girls, compared to the current situation, was US$33,000/QALY gained. Mandatory vaccination appeared least cost-effective (ICER compared to school-based of US$117,000/QALY gained, but with wide 95% uncertainty limits from $56,000 to $220,000). All interventions generated more QALYs per 12-year-old for Māori (indigenous population) and people living in deprived areas (range 5-25% greater QALYs gained).

INTERPRETATION

A more intensive school-only vaccination programme seems warranted. Reductions in vaccine price will greatly improve cost-effectiveness of all options, possibly making a law for mandatory vaccination optimal from a health sector perspective. All interventions could reduce ethnic and socioeconomic disparities in HPV-related disease.

Modeling the impact of screening policy and screening compliance on incidence and mortality of cervical cancer in the post-HPV vaccination era

BACKGROUND

In Norway, pap smear screening target women aged 25-69 years on a triennial basis. The introduction of human papillomavirus (HPV) mass immunization in 2009 raises questions regarding the cost-saving future changes to current screening strategies.

METHODS

We calibrated a dynamic HPV transmission model to Norwegian data and assessed the impact of changing screening 20 or 30 years after vaccine introduction, assuming 60 or 90% vaccination coverage. Screening compliance among vaccinated women was assumed at 80 or 50%. Strategies considered: (i) 5-yearly screening of women of 25-69 years, (ii) 3-yearly screening of women of 30-69 years and (iii) 3-yearly screening of women of 25-59 years.

RESULTS

Greatest health gains were accomplished by ensuring a high vaccine uptake. In 2060, cervical cancer incidence was reduced by an estimated 36-57% compared with that of no vaccination. Stopping screening at the age of 60 years, excluding opportunistic screening, increased cervical cancer incidence by 3% (2060) compared with maintaining the current screening strategy, resulting in 1.0-2.4% extra cancers (2010-2060). The 5-yearly screening strategy elevated cervical cancer incidence by 30% resulting in 4.7-11.3% additional cancers.

CONCLUSION

High vaccine uptake in the years to come is of primary concern. Screening of young women <30 years remains important, even under the conditions of high vaccine coverage.

Value for money from HPV vaccination and cervical screening

Introduction of human papillomavirus (HPV) vaccination programs raises some important questions about the future organization of cervical screening programs. Two studies--from NZ and Canada--have addressed the question of what combination of vaccination and screening strategies might be most cost-effective in preventing cervical cancer. Both studies indicate that some modifications to existing screening programs may be desirable as immunized females enter these programs. Variables in HPV vaccination that are likely to be particularly important for determining the future cost-effectiveness of cervical screening programs include: vaccine uptake rate, compliance with full doses, timely completion of doses, duration of protection, male vaccination and HPV infection rate. If value for money is to be achieved, it is important that the appropriate data are collected so that policy makers can consider the combined impact of these two programs on costs and health outcomes.