Article Text

Original article
Adolescent and parental utilities for the health states associated with pelvic inflammatory disease
1. Maria Trent1,2,
2. Harold P Lehmann1,3,
3. Qiang Qian4,
4. Carol B Thompson5,
5. Jonathan M Ellen1,2,
6. Kevin D Frick1,3
1. 1Department of Pediatrics, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
2. 2Department of Population, Family and Reproductive Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
3. 3Department of Health Policy and Management, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
4. 4Hao Han Technologies, LLC, Baltimore, Maryland, USA
5. 5Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
1. Correspondence to Dr Maria Trent, Department of Paediatrics, Johns Hopkins School of Medicine, 200 N Wolfe Street, #2064, Baltimore, MD 21287, USA; mtrent2{at}jhmi.edu

## Abstract

Purpose There is limited information about how the consumers of adolescent pelvic inflammatory disease (PID) care value health states associated with the disorder. The aim of this study is to determine and compare adolescent and parent PID-related health utilities.

Methods Adolescent girls (N=134) and parents (N=121) completed a web-based utility elicitation survey. Participants reviewed five scenarios describing the health states associated with PID (outpatient treatment (mild–moderate disease), inpatient treatment (severe disease), ectopic pregnancy, infertility and chronic abdominal pain). After each scenario, participants were asked to rate health-related quality of life (HRQL) using a Visual Analogue Scale (VAS) and to complete a time trade-off (TTO) assessment. Data were evaluated using multiple linear (VAS) and quantile (TTO) regression analyses.

Results Adolescents had significantly lower mean valuations (p<0.01) than the parents on the VAS for HRQL in each health state (outpatient (62 vs 76), inpatient (57 vs 74), ectopic (55 vs 73), infertility (59 vs 68) and chronic abdominal pain (48 vs 61)). Using quantile regression analysis, adolescents were also willing to give up more time for health gains indicated by lower median TTO scores (p<0.01) for outpatient treatment (0.98 vs 1.0), inpatient treatment (0.96 vs 1.0) and ectopic pregnancy (0.98 vs 1.0).

Conclusions The authors demonstrate that adolescents assign more disutility (lower valuations) than parents for HRQL and three of five of the TTO assessments for PID-related health states. Future economic evaluations using patient-specific preferences to determine resource allocation for PID management in adolescents should include adolescent health outcomes and utilities.

• women
• sexual health
• polycystic ovarian
• reproductive health
• AIDS
• behavioural interv
• sexual practices

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## Introduction

Health utility assessment is a critical component of economic evaluation in healthcare. Health utilities measure people's feelings about specific health states using values that can be compared between different conditions. Health utilities are values that numerically reflect people's preferences for one health state relative to another.1 To date, economic analyses to determine resource allocation for pelvic inflammatory disease (PID) treatment have been driven by adult outcomes and preferences.2 3 There is currently no existing data on patient or parent preferences (utilities) related to adolescent sexually transmitted infection (STI) or PID care.4 However, there is sufficient precedent in the literature to suggest that the availability of these preferences may have significant policy implications as cost analyses drive resource allocation in the USA.5–7 We have been unable to effectively select an optimal approach to PID treatment for adolescents because ‘optimal’ status depends on the preferences of consumers (adolescent patients and potentially their parents) of care, or in the case where they differ, requires a discussion across the key stakeholder groups.

There has also been significant debate on whether adolescents are sufficiently equipped to provide utility data, resulting in use of proxy utility and quality of life assessments.8 Unlike younger children, adolescents are often seeking and receiving confidential care without the assistance of an activated and engaged parent9; therefore, utility elicitation from adolescents (and not proxies) is both reasonable and necessary. Analyses that also integrate the parental perspective facilitate adolescent autonomy while also integrating parents' desires for their daughters into the design of the optimal treatment approach for urban adolescents.

Given the limited information about how the consumers of adolescent PID care value the health states associated with the disorder, additional research is warranted. The aim of this study is to measure and compare adolescent and parent PID-related health utilities from a community perspective.

## Methods

Trained research assistants recruited adolescent girls and parents of adolescents from an academic paediatric and adolescent medicine clinic and five health department school-based health clinics in a large urban community with high STI prevalence. Adolescents were eligible for the study if they were women, 12–19 years of age, English speaking and without significant cognitive impairment that would prohibit completion of the survey. Parents were eligible if they were adults older than 18 years of age who had raised an adolescent and/or were currently parenting an adolescent over 12 years of age at the time of the interview. The term ‘parent’ was broadly applied in these criteria to include biological parents, foster parents, legal guardians and individuals parenting through informal kinship ties (aunts, uncles and older siblings). The web program automatically records all individuals who agree to review the study information and then indicates if the participant completed the survey as a ‘true’ result. If participants did not complete the survey, name and contact information without incomplete survey data was saved in the program.

Research staff used the web-based platform to review study procedures and the online consent form with adolescents and parents in a quiet area in the clinic. Individuals who agreed to participate in the study were provided assistance by the trained research assistants to complete each stage of the questionnaire during the online session. After completing a basic demographic survey, participants reviewed the five scenarios describing the medical, functional, activity and social impacts of the health states associated with PID (outpatient treatment (mild–moderate disease), inpatient treatment (moderate–severe disease), ectopic pregnancy, infertility and chronic abdominal pain (CAP). The adolescents were asked to respond for themselves, and the parents were asked to respond for their child.

We solicited preferences from participants in two ways. One method is the ‘Visual Analogue Scale’ (VAS), where no trade-off is elicited, but the participant rates the burden on a scale from 0 (immediate death) to 100 (a normal, unburdened life). The other is the ‘time trade-off (TTO)’ method, where the participant must make a trade-off between a longer life with a burden (eg, CAP) and a shorter life without a burden (in perfect health). The number of years or months with the burden that the participant is willing to give up, to avoid the burden, gives an indication about the perceived unpleasantness (‘disutility’) of the burden.

Each interview lasted approximately 30 min and participants received a $5 gift card in remuneration for their time upon completion of the survey. This study was approved by the Johns Hopkins Medicine Institutional Review Board and the Baltimore City Health Department Research Review Committee. ### Data analysis Summary statistics were generated for each of the descriptive variables and the primary outcome variables using STATA V.11 (STATA Corp LP, 2009). Comparisons of group differences on the outcome variables were performed using t tests or Mann–Whitney U tests, depending on the distribution of the outcome. Outcome variables were also analysed, using linear regression when model assumptions held and with non-parametric quantile regression (estimating the median of the outcome variable) otherwise.11 12 Given the current health disparities regarding STI and the potential impact of prior individual STI history on utility assessments, minority status and history of PID were evaluated as potential confounders in the models. ## Results ### Selected demographics All adolescents and parents who entered the online process completed the survey. Health state valuations were obtained from 121 parents and 134 adolescent girls. Most adolescents (76%) and parents (67%) were African–American. Most parents were employed outside the home (76%) and had household incomes >$30 000 per year (75.7%). While few adolescents and mothers had a history of PID or related PID sequelae, 25% of parents and 20% of adolescents had a history of an STI (table 1).

Table 1

Selected demographics by group status

### Comparison of adolescent and parental utilities

Mean and median values for the HRQL as measured by the VAS and the TTO values are shown in table 2. Adolescents had significantly lower mean valuations (p<0.01) than the parents on the VAS for HRQL in each health state (outpatient (62 vs 76), inpatient (57 vs 74), ectopic (55 vs 73), infertility (59 vs 68) and CAP (48 vs 61)) meaning that they perceived lower HRQL. Using quantile regression analysis, adolescents were also willing to give up more time for health gains indicated by lower median TTO scores (p<0.01) for outpatient treatment (0.98 vs 1.0), inpatient treatment (0.96 vs 1.0) and ectopic pregnancy (0.98 vs 1.0). Quantile regression was used to evaluate continuous TTO outcomes because parents and adolescents were not willing to sacrifice substantial amounts of months or years of life lost for a non-threatening health state resulting in non-normally distributed data with a significant skew towards 1 (ceiling effect). Despite these findings, adolescents were willing to give up significantly more time for health gains indicated by lower median TTO scores for outpatient treatment, inpatient treatment and ectopic pregnancy compared with parents. These median differences in TTO translate into an additional 1 year out of 50 years to prevent outpatient PID and ectopic pregnancy and 2 years to prevent PID requiring a hospital stay (table 3).

Table 2

Valuation of health states using the Visual Analogue Scale (VAS) and time trade-off (TTO) exercise mean VAS and median TTO health utility valuations and summary results of linear and quantile regression analyses

Table 3

Summary results of linear (VAS) and quantile regression analyses (TTO) contrasting adolescent and parent reports

## Discussion

This study provides the first estimates of health utility associated with PID among adolescents and the parents of adolescents. These measures can be used in economic analyses that assess cost and preventable disease burden estimates. By comparing the adolescent and parent utilities, we demonstrate that parents consistently assign less the disutility than adolescents for all of the HRQL and three of five of the TTO assessments for the health states associated with PID.

We used standard approaches, recommended by established authors1 and used by the most comparable study, done in adults.2 In particular, preferences were assessed in two ways: without trade-offs (VAS) and with trade-offs (TTO). Although our time horizon is long, eliciting time preferences (ie, experiencing outcomes early vs later) would not be expected to change the results in this context.12–14 The scenarios used and our methods of data collection are true to the work among an adult cohort conducted by Smith and colleagues2 with minor adaptations for the audience targeted by this work.

Our findings must also be considered in light of several general study limitations. These data were collected from adolescents and parents in paediatric and adolescent clinical settings in a single urban community in the USA that has been greatly affected by STI and so the findings may not be generalisable to other dissimilar communities. However, these findings are important given the significant health disparities faced by urban teens in this and similar communities and are reflective of community from which previous PID utility assessments were determined. The estimates can also be used to provide better ranges for adolescent-related economic analyses. While our computerised system captured each individual who logged into review the study protocol even if they did not complete the survey, it does not capture those individuals who may have been asked to participate by clinical staff as a part of the referral process and so we may overestimate study acceptance rates for this study. Finally, the sample of girls within this cohort who actually had PID was limited so we were unable to determine the differences between girls with a history of PID compared with those who did not. Our data, however, are reflective of the perspective of the general community of medical care users: a view that is preferred compared with use of valuations from only those affected by a disorder in economic analyses.15

The 50-year time horizon was used in our scenarios because the sequelae of PID last for decades and our team was concerned that the 10-year estimate used in prior work was not reflective of the true life course for an adolescent girl before or after a diagnosis in PID and that using the shorter time frame would drastically alter decision making for adolescent girls and their parents in the context of the TTO exercises. This means that caution must be used when contrasting the findings from previously published adult cohorts with and without PID. While the study by Smith et al1 informed our work, their investigative team only enrolled women aged 18 years and older. In comparison with our results, adult women with PID assigned generally lower VAS scores than adolescents, potentially indicating more optimism among adolescents. A similar ceiling effect was observed for the TTO exercise scores in both studies. This unwillingness to sacrifice significant portions of life is consistent with the notion that PID is an illness that has significant impacts on HRQL2 16 but not for which the actual risk of death is greater or the length of life is generally thought to be shorter.

In viewing the mean VAS and median TTO scores in our study in contrast to the Smith study of urban women, adolescents in our group were willing to evaluate the scenario to rate HRQL and then actually make trade-offs in more than one scenario. While adult women without a history of PID often rate HRQL lower than adolescent girls, they were not as willing to make trade-offs to prevent a life with the PID health states as indicated by a median TTO of 1 for all but the pelvic pain scenarios. This may be in part due to the short time horizon used in the study (10-year window) or life experience such has already having children or being hospitalised for something else that shaped their perspective on the value of the trade.

In summary, this study demonstrates that the consumers of PID services perceive significant disruption in HRQL when given the opportunity to evaluate potential outcomes associated with the disorder. Considering the adolescent girl as the gold standard for development of adolescent-oriented PID utilities and eventual healthcare interventions, our findings suggest that parents may underestimate the degree to which PID and related health states impact on the preferences given by adolescent girls in a community sample of those using healthcare. Given that the adolescent valuations show values and patterns consistent with findings from adult research, future economic evaluations for which patient-specific preferences are used to determine resource allocation for PID management in adolescents should consider inclusion of adolescent health outcomes and utilities.

### Key messages

• Adolescent girls and parents of adolescents perceive significant disruption in health-related quality of life when given the opportunity to evaluate potential outcomes associated with the disorder.

• Adolescents perceive lower heath-related quality of life and are willing to trade more time to prevent pelvic inflammatory disease-related health states than adolescents.

• Future economic evaluations employing the patient perspective to determine resource allocation for pelvic inflammatory disease management in adolescents should consider inclusion of adolescent health utilities.

## Acknowledgments

We are grateful to Dr Kenneth Smith for sharing the electronic survey used in his work with adult women for use in our adolescent-focused and web-based study methods.

## Footnotes

• Funding This study was funded by the Centers for Disease Control and Prevention (K01 DP00128-02).

• Competing interests None.

• Ethics approval Ethics approval was provided by Johns Hopkins University Institutional Review Board; Baltimore City Health Department Research Review Committee.

• Provenance and peer review Not commissioned; externally peer reviewed.