Proceedings of the Modeling Evidence in HPV Pre-Conference Workshop in Malmö, Sweden, May 9-10, 2009

Mathematical Models for Evaluating Effectiveness and Cost-Effectiveness of Cervical Cancer Control Policies in Populations Including Women Living With Human Immunodeficiency Virus: A Scoping Review

OBJECTIVES

Mathematical modeling is increasingly used to inform cervical cancer control policies, and model-based evaluations of such policies in women living with human immunodeficiency virus (HIV) are an emerging research area. We did a scoping review of published literature to identify research gaps and inform future work in this field.

METHODS

We systematically searched literature up to April 2022 and included mathematical modeling studies evaluating the effectiveness or cost-effectiveness of cervical cancer prevention strategies in populations including women living with HIV. We extracted information on prevention strategies and modeling approaches.

RESULTS

We screened 1504 records and included 22 studies, almost half of which focused on South Africa. We found substantial between-study heterogeneity in terms of strategies assessed and modeling approaches used. Fourteen studies evaluated cervical cancer screening strategies, 7 studies assessed human papillomavirus vaccination (with or without screening), and 1 study evaluated the impact of HIV control measures on cervical cancer incidence and mortality. Thirteen conducted cost-effectiveness analyses. Markov cohort state-transition models were used most commonly (n = 12). Most studies (n = 17) modeled the effect of HIV by creating HIV-related health states. Thirteen studies performed model calibration, but 11 did not report the calibration methods used. Only 1 study stated that model code was available upon request.

CONCLUSIONS

Few model-based evaluations of cervical cancer control strategies have specifically considered women living with HIV. Improvements in model transparency, by sharing information and making model code publicly available, could facilitate the utility of these evaluations for other high disease-burden countries, where they are needed for assisting policy makers.

HPV-FRAME: A consensus statement and quality framework for modelled evaluations of HPV-related cancer control

Intense research activity in HPV modelling over this decade has prompted the development of additional guidelines to those for general modelling. A specific framework is required to address different policy questions and unique complexities of HPV modelling. HPV-FRAME is an initiative to develop a consensus statement and quality-based framework for epidemiologic and economic HPV models. Its development involved an established process. Reporting standards have been structured according to seven domains reflecting distinct policy questions in HPV and cancer prevention and categorised by relevance to a population or evaluation. Population-relevant domains are: 1) HPV vaccination in pre-adolescent and young adolescent individuals; 2) HPV vaccination in older individuals; 3) targeted vaccination in men who have sex with men; 4) considerations for individuals living with HIV and 5) considerations for low- and middle-income countries. Additional considerations applicable to specific evaluations are: 6) cervical screening or integrated cervical screening and HPV vaccination approaches and 7) alternative vaccine types and alternative dosing schedules. HPV-FRAME aims to promote the development of models in accordance with an explicit framework, to better enable target audiences to understand a model's strength and weaknesses in relation to a specific policy question and ultimately improve the model's contribution to informed decision-making.

Anatomical structure, and expression of CCL4 and CCL13-like during the development of maxillary barbel in Paramisgurnus dabryanus

Paramisgurnus dabryanus is one of the most economically important fishes in China. Barbels are an essential sensory organ for the food-seeking ability of teleost fish. However, the anatomical structure of the maxillary barbels of P. dabryanus and the molecular basis of their development are unknown. We investigated the anatomical structure of the barbel, and gene expression patterns of two chemokine C-C motif ligands: CCL4 and CCL13-like during the maxillary barbel development using Masson Trichrome staining, light and electron microscopy, and qPCR. Anatomically, the maxillary barbel of P. dabryanus contains taste buds, melanophores, collagen fibers, connective tissue, smooth muscles, nerve bundles, and blood vessels, but does not have skeletal muscles or a skeleton rod. The expression of CCL4 and CCL13-like was weak or non-existent in the early phases of development, but high at the last two studied time-points: 192- and 216-h post-hatching. Results indicated that CCL4 and CCL13-like were related to the development of the maxillary barbel.

Buprenorphine/naloxone induction for treatment of acute on chronic pain using a micro-dosing regimen: A case report

Background: Due to its unique pharmacologic properties, efficacy as an analgesic, and role as a first-line medication for the treatment of opioid use disorder, sublingual buprenorphine has emerged as a treatment for patients with concurrent chronic pain and opioid use disorders. One challenge to utilizing buprenorphine is that precipitated opioid withdrawal can result if this medication is initiated in the presence of other opiates with lesser binding affinities. Micro-dosing induction regimens utilize a slower titration to avoid the need for a period of abstinence from other opiates and decrease the risk of precipitated withdrawal.

Aims: The aim of this article is to present a case where a standardized micro-dosing induction regimen was used to transition a patient from other opiate analgesia to a sublingual formulation of buprenorphine/naloxone.

Methods: This case took place on an inpatient neurosurgical unit of a Canadian tertiary-care city hospital. Written informed consent was collected prior to a detailed chart review.

Results: Here we present a case of a postoperative neurosurgical inpatient who was referred to our team for pain management in the context of chronic pain and a past history of opioid use disorder. She was successfully transitioned to buprenorphine/naloxone, replacing all other opioid analgesia, without a period of opioid withdrawal using a micro-dosing induction regimen.

Conclusions: Sublingual buprenorphine/naloxone can be safe and effective for treatment of chronic pain, particularly for those with past or current opioid use disorder. Micro-dosing provides a preferable induction strategy for patients who are not able to tolerate the requirement for moderate opioid withdrawal prior to initiation with existing regimens.

Cost-effectiveness of the 13-valent pneumococcal conjugate vaccine in adults in Portugal versus "no vaccination" and versus vaccination with the 23-valent pneumococcal polysaccharide vaccine

The burden of pneumococcal disease in adults is substantial from a social and economic point of view. This study assessed the cost-effectiveness of the 13-valent pneumococcal conjugate vaccine (PCV13) for the prevention of invasive pneumococcal disease and pneumococcal pneumonia in adults versus "no vaccination" and versus vaccination with the 23-valent pneumococcal polysaccharide vaccine (PPSV23). A Markov model was used to simulate three strategies: no vaccination, complete vaccination with PPSV23 and complete vaccination with PCV13. The comparison between strategies allowed the estimation of clinical and economic outcomes including incremental cost-effectiveness ratios (ICER) and incremental cost-utility ratios (ICUR). The model took into account the distributions of age, risk profile, vaccination status, type of immunization and time since vaccination in the population. A societal perspective was adopted and a lifetime horizon was considered. Different sources of data and assumptions were used to calibrate PPSV23 and PCV13 effectiveness. Inpatient costs were based on the 2013 diagnosis-related group (DRG) database for National Health Service (NHS) hospitals and expert opinion; NHS official tariffs were the main source for unitary costs. PCV13 shows ICURs of €17,746/QALY and €13,146/QALY versus "no vaccination" and vaccination with PPSV23, respectively. Results proved to be robust in univariate sensitivity analyses, where all ratios were below a €20,000 threshold, with the exception of the scenario with PCV13 effectiveness halved. In a probabilistic sensitivity analysis, 94% of simulations showed cost-effectiveness ratios lower than €20,000/QALY, in both strategies. It was found that PCV13 is a cost-effective strategy to prevent pneumococcal disease in adults in Portugal.

Systematic review of model-based cervical screening evaluations

BACKGROUND

Optimising population-based cervical screening policies is becoming more complex due to the expanding range of screening technologies available and the interplay with vaccine-induced changes in epidemiology. Mathematical models are increasingly being applied to assess the impact of cervical cancer screening strategies.

METHODS

We systematically reviewed MEDLINE®, Embase, Web of Science®, EconLit, Health Economic Evaluation Database, and The Cochrane Library databases in order to identify the mathematical models of human papillomavirus (HPV) infection and cervical cancer progression used to assess the effectiveness and/or cost-effectiveness of cervical cancer screening strategies. Key model features and conclusions relevant to decision-making were extracted.

RESULTS

We found 153 articles meeting our eligibility criteria published up to May 2013. Most studies (72/153) evaluated the introduction of a new screening technology, with particular focus on the comparison of HPV DNA testing and cytology (n = 58). Twenty-eight in forty of these analyses supported HPV DNA primary screening implementation. A few studies analysed more recent technologies - rapid HPV DNA testing (n = 3), HPV DNA self-sampling (n = 4), and genotyping (n = 1) - and were also supportive of their introduction. However, no study was found on emerging molecular markers and their potential utility in future screening programmes. Most evaluations (113/153) were based on models simulating aggregate groups of women at risk of cervical cancer over time without accounting for HPV infection transmission. Calibration to country-specific outcome data is becoming more common, but has not yet become standard practice.

CONCLUSIONS

Models of cervical screening are increasingly used, and allow extrapolation of trial data to project the population-level health and economic impact of different screening policy. However, post-vaccination analyses have rarely incorporated transmission dynamics. Model calibration to country-specific data is increasingly common in recent studies.

Development of a quality framework for models of cervical screening and its application to evaluations of the cost-effectiveness of HPV vaccination in developed countries

BACKGROUND

HPV vaccination has now been introduced in most developed countries, but this has occurred in the context of established cervical cancer screening mechanisms which provide population-level protection against the most common HPV-related cancer. Therefore, estimating the cost-effectiveness of HPV vaccination to further reduce HPV-related disease depends in large part on the estimation of the effectiveness of the cervical screening 'background'. The aim of this study was to systematically review and assess methods for simulating cervical screening in decision analytic models used for evaluation of HPV vaccination.

METHODS

Existing quality frameworks for economic models were extended to develop a specific quality framework for models of cervical screening. This involved domains for model structure, parameterisation (data sources) and validation (consistency). A systematic review of economic evaluations of HPV vaccination was then conducted, and assessment of cervical screening model components was then performed via application of the new quality framework.

RESULTS

Generally, models took into account population-level cervical screening participation, but were inconsistent in their approach to modelling abnormal smear management, diagnostic evaluation and treatment of precancerous disease. There was also considerable variability in the accuracy of modelling clinical pathways and the scope of validation performed for screening-related outcomes, with focus directed towards cervical cancer targets. Only a few models comprehensively validated against observed pre-cancerous abnormalities.

CONCLUSION

Models of HPV vaccination in developed countries can be improved by further attention to the 'background' modelling of secondary protection via cervical screening. The quality framework developed for this review can be used to inform future HPV vaccination evaluations, including evaluations of the cost-effectiveness of male vaccination and next generation HPV vaccines, and to assess models used to evaluate new cervical screening technologies and recommendations.

Cost-effectiveness of human papillomavirus vaccination in low and middle income countries: a systematic review

The World Health Organization recommends establishing that human papillomavirus vaccination is cost-effective before vaccine introduction. We searched Pubmed, Embase and the Cochrane Library to 1 April 2012 for economic evaluations of human papillomavirus vaccination in low and middle income countries. We found 25 articles, but almost all low income countries and many middle income countries lacked country-specific studies. Methods, assumptions and consequently results varied widely, even for studies conducted for the same country. Despite the heterogeneity, most studies conclude that vaccination is likely to be cost-effective and possibly even cost saving, particularly in settings without organized cervical screening programmes. However, study uncertainty could be reduced by clarity about vaccine prices and vaccine delivery costs. The review supports extending vaccination to low income settings where vaccine prices are competitive, donor funding is available, cervical cancer burden is high and screening options are limited.

Economic analyses to support decisions about HPV vaccination in low- and middle-income countries: a consensus report and guide for analysts

Low- and middle-income countries need to consider economic issues such as cost-effectiveness, affordability and sustainability before introducing a program for human papillomavirus (HPV) vaccination. However, many such countries lack the technical capacity and data to conduct their own analyses. Analysts informing policy decisions should address the following questions: 1) Is an economic analysis needed? 2) Should analyses address costs, epidemiological outcomes, or both? 3) If costs are considered, what sort of analysis is needed? 4) If outcomes are considered, what sort of model should be used? 5) How complex should the analysis be? 6) How should uncertainty be captured? 7) How should model results be communicated? Selecting the appropriate analysis is essential to ensure that all the important features of the decision problem are correctly represented, but that the analyses are not more complex than necessary. This report describes the consensus of an expert group convened by the World Health Organization, prioritizing key issues to be addressed when considering economic analyses to support HPV vaccine introduction in these countries.

Differential expression of cellular microRNAs in HPV-11 transfected cells. An analysis by three different array platforms and qRT-PCR

Human papillomavirus type 11 (HPV-11) infects the genital and the respiratory tract leading to condylomas and respiratory papillomatosis. HPV infections are restricted to epithelial tissue and the progression through the virus lifecycle is tightly coordinated to the differentiation of the host cell. The changes of cellular microRNAs by HPV-11 gene expression were investigated in a cell culture model of HaCaT cells transfected with HPV-11, with the goal of understanding which cellular processes were affected by the virus. Human microRNA profiling was conducted on three different array platform systems and because very few microRNAs (miR-663, -638, -149* and -92b*) were consistently found in all three array data sets we performed extensive statistical analyses of the array data and the qRT-PCR validation. We assume that the most reliable differentially expressed microRNAs are the ones identified by more than one array platform. We also show that TaqMan® qRT-PCR validation is of limited use for less abundant microRNAs.

Proceedings of the Modeling Evidence in HPV Pre-Conference Workshop in Malmö, Sweden, May 9-10, 2009

BACKGROUND

Prominent published and active human papillomavirus (HPV) modelers from around the world were invited to participate in the inaugural Modeling Evidence in HPV (MEHPV) Pre-Conference Workshop on May 9-10, 2009, in Malmö, Sweden. The workshop took place directly before the 25th International Papillomavirus Conference.

OBJECTIVES

The aim of the workshop was to develop an international network of investigators engaged in HPV modeling and to facilitate open discussion about the structure and parameterization of models, as well as other methodologic concerns.

METHODS

Thirty-four participants from more than a dozen countries and a variety of settings, representing the authors or coauthors of 82% of the HPV modeling literature, exchanged ideas on fundamental questions in the field. These proceedings, based on the 217-page transcript, were assembled by the Scientific Committee to summarize the ideas of workshop participants in a deidentified, readable fashion. They represent the work and recorded opinions of session participants and do not constitute the official positions of participants as a whole or individually, the Scientific Committee, or any sponsoring organization or entity.

RESULTS

In charting a path forward, 3 topics emerged as most pressing: best practices for HPV modeling, comparative modeling, and modeling in developing countries.

CONCLUSION

This summary of the proceedings of the preconference workshop on HPV modeling characterizes many of the prominent contemporary issues in the field.