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author:("plei, Andreas")
1.  Evaluation of the American-English Quality of Life in Short Stature Youth (QoLISSY) questionnaire in the United States 
The European Quality of Life in Short Stature Youth (QoLISSY) is a novel condition-specific instrument developed to assess health related quality of life (HrQoL) in children/adolescents with short stature from patient and parent perspectives. Study objective was to linguistically validate and psychometrically test the American-English version of the QoLISSY instrument.
Upon conversion of the British-English version to American-English, content validity and acceptance of the questionnaire were examined through focus group discussions with cognitive debriefing in 28 children/adolescents with growth hormone deficiency (GHD) or idiopathic short stature (ISS) and their parents. In the subsequent field test with 51 families and a re-test with 25 families the psychometric performance of the American-English version was examined and compared with the original European dataset.
Pilot test results supported the suitability of the American-English version. Good internal consistency with Cronbach’s Alpha ranging from 0.84 to 0.97 and high test-re-test reliabilities were observed in the field test. The QoLISSY was able to detect significant differences according to the degree of short stature with higher HrQoL for taller children. Correlations with a generic HrQoL tool support the QoLISSY’s concurrent validity. The scale’s operating characteristics were comparable to the original European data.
Results support that the QoLISSY American-English version is a psychometrically sound short stature-specific instrument to assess the patient- and parent- perceived impact of short stature. The QoLISSY instrument is fit for use in clinical studies and health services research in the American-English speaking population.
PMCID: PMC4424504  PMID: 25889818
Short stature; Health related quality of life; Children; Questionnaire development; Psychometric properties
2.  Results from an international multicenter trial evaluating the ease-of-use of and preference for a newly developed disposable injection pen for the treatment of growth hormone deficiency in treatment-naïve children and adults 
Previous research has reported that ease of use of and preference for a delivery device are associated with greater patient compliance – an important factor in achieving optimal therapeutic results. The objective of this study was to assess the ease-of-use of a new disposable pen (GoQuick®, Pfizer, Inc.) versus the current reusable pen (GENOTROPIN Pen®, Pfizer, Inc.) to inject a daily dose of recombinant DNA origin human growth hormone, Genotropin® (somatropin) in standard practice. In this randomized, crossover, multicenter, multinational, open-label study, ease-of-use of and preference for the two pens were assessed in three treatment-naïve populations: 1) parents of very young children; 2) parent–child dyads; and 3) adults via use of a validated self-report Injection Pen Assessment Questionnaire (IPAQ) after 2 months of at-home-use experience. The primary endpoint was the proportion of participants who reported the new disposable pen to be no different from or easier to use than the current reusable pen. Safety was also assessed and reported according to local legal requirements. Of the 120 screened patients, 119 were included in the ease-of-use analysis and all were included in the safety analyses. In all, 67.2% found the new somatropin disposable pen to be no different from or easier to use than the reusable pen (95% confidence interval: 58.8–75.7). Most adverse events were mild or moderate. No deaths or device- or treatment-related serious adverse events were reported. These results suggest that improvements made to the reusable somatropin pen are tangible and recognizable to treatment-naïve patients and their caregivers, child–caregiver dyads, and adults, and may positively impact continued compliance with therapy.
Registry information identifier: NCT01112865.
PMCID: PMC3990392  PMID: 24748824
somatropin; disposable injection pen; ease-of-use; Injection Pen Assessment Questionnaire; preference; recombinant human growth hormone
3.  Assessing the quality of life of health-referred children and adolescents with short stature: development and psychometric testing of the QoLISSY instrument 
When evaluating the outcomes of treatment in paediatric endocrinology, the health-related quality of life (HrQoL) of the child is to be taken into consideration. Since few self–reported HrQoL instruments exist for children with diagnosed short stature (dSS), the objective of this study was to develop and psychometrically test a targeted HrQoL instrument for use in multinational clinical research.
The target population were short stature (height < −2 SDS) children and adolescents (age 8–12 and 13–18 years) with a diagnosis of growth hormone deficiency (GHD) or idiopathic short stature (ISS), differing in growth hormone treatment status. Focus group discussions for concept and item generation, piloting of the questionnaire with cognitive debriefing, and instrument field testing with a retest were conducted simultaneously in five countries. After qualitative and preliminary quantitative analyses, psychometric testing of field test data in terms of reliability and validity including confirmatory factor analyses (CFA) was performed.
Following item generation from focus group discussions, 124 items were included in a pilot test with a cognitive debriefing exercise providing preliminary feedback on item and domain operating characteristics. A field test with 268 participants showed high internal consistency reliabilities (alpha 0.82 – 0.95), good correlations with generic measures (up to r = .58), significant known group differences (e.g. in height: F = 32, df 244, p < 0.001) and an acceptable CFA model fit suggesting construct validity of the three-domain core structure with 22 items, supplemented by three mediator domains with 28 items.
The QoLISSY questionnaire is a promising step forward in assessing the impact of dSS on HrQoL. It is based on items generated from the subjective experience of short stature children referred for endocrine investigation, is validated for use in five languages and it is easy to administer in clinical and research settings.
PMCID: PMC3666886  PMID: 23648112
Health-related quality of life; Short stature; Growth hormone deficiency; Assessment in children; Idiopathic short stature; Outcomes research; Patient reported outcomes
4.  Psychometric validation of the visual function questionnaire-25 in patients with diabetic macular edema 
Diabetic Macular Edema (DME) is a common cause of impaired vision and blindness amongst diabetics. If not detected and treated early, the resulting vision loss can lead to considerable health costs and decreased health-related quality of life (HRQoL). The aim of this study was to provide evidence of the psychometric properties of the National Eye Institute - Visual Functioning Questionnaire (VFQ-25) for use in a cohort of DME patients who participated in a clinical efficacy and safety trial of pegaptinib sodium (Macugen).
A phase 2/3 randomised, double masked trial evaluated pegaptanib injection versus sham injection in patients with DME. The analysis was conducted using baseline HRQoL data of the VFQ-25 and the EQ-5D, on a modified intent-to-treat sample of 235 patients. These measures were administered by a trained interviewer by telephone in all but one of the study countries, where face-to-face interviews were conducted in the clinic. The measures were completed in the week prior to baseline, and after 54 weeks of treatment. Distance visual acuity, measured according to the Early Treatment Diabetic Retinopathy Study (ETDRS), was assessed at all time points. Psychometric properties of the VFQ-25 assessed included domain structure, reliability, concurrent and construct validity, responsiveness.
The VFQ-25 was found to consist of 11 domains slightly different than those proposed. Nevertheless, none of the eight established multi-item scales met the criterion for further splitting and the VFQ-25 was scored as in the developers’ instructions. Internal consistency reliability was demonstrated for six out of the eight original multi-item scales, with Cronbach's alpha ranging from 0.58 (Distance Activities) to 0.85 (Vision Specific: Dependency). The VFQ-25 domains generally showed a low to moderate correlation with EQ-5D visual analogue scale (range 0.16-0.43) and with the visual acuity score (range 0.10-0.41). Construct validity was upheld with higher VFQ-25 scores for patients who saw more letters according to the ETDRS. Almost all scales were shown to be responsive with Guyatt's statistic ranging from 0.10 to 0.56 at 54 weeks.
The VFQ-25 has evidence to support its validity and reliability for measuring HRQoL in DME. However, some operating characteristics of the instrument need further consideration and discussion in the case of DME patients. Further research is therefore warranted in this indication.
PMCID: PMC3599421  PMID: 23347793
Diabetic macular edema; Visual functioning questionnaire; Psychometric analyses
5.  Psychometric Assessment of the Injection Pen Assessment Questionnaire (IPAQ): measuring ease of use and preference with injection pens for human growth hormone 
To examine the psychometric properties of the Injection Pen Assessment Questionnaire (IPAQ) including the following: 1) item and scale characteristics (e.g., frequencies, item distributions, and factor structure), 2) reliability, and 3) validity.
Focus groups and one-on-one dyad interviews guided the development of the IPAQ. The IPAQ was subsequently tested in 136 parent–child dyads in a Phase 3, 2-month, open-label, multicenter trial for a new Genotropin® disposable pen. Factor analysis was performed to inform the development of a scoring algorithm, and reliability and validity of the IPAQ were evaluated using the data from this two months study. Psychometric analyses were conducted separately for each injection pen.
Confirmatory factor analysis provides evidence supporting a second order factor solution for four subscales and a total IPAQ score. These factor analysis results support the conceptual framework developed from previous qualitative research in patient dyads using the reusable pen. However, the IPAQ subscales did not consistently meet acceptable internal consistency reliability for some group level comparisons. Cronbach’s alphas for the total IPAQ score for both pens were 0.85, exceeding acceptable levels of reliability for group comparisons.
The total IPAQ score is a useful measure for evaluating ease of use and preference for injection pens in clinical trials among patient dyads receiving hGH. The psychometric properties of the individual subscales, mainly the lower internal consistency reliability of some of the subscales and the predictive validity findings, do not support the use of subscale scores alone as a primary endpoint.
PMCID: PMC3519573  PMID: 23046797
Patient-reported outcome; Injection device (pen); Ease of use; Parent–child dyads; Growth hormone (GH)
6.  Patient preferences in the treatment of diabetic retinopathy 
Accounting for patient preferences may be especially important in diabetes mellitus, given the challenge in identifying factors associated with treatment adherence. Although preference studies have been performed in diabetes, none have examined treatments used in diabetic retinopathy (DR). The objective of this study was to elicit patient preferences for attributes associated with antivascular endothelial growth factor, focal and panretinal laser, and steroid therapy used in DR management.
A cross-sectional conjoint survey was administered to DR patients at three Canadian eye centers. The survey involved making tradeoffs among 11 DR treatment attributes, including the chance of improving vision and risks of adverse events over a 1-year treatment period. Attribute utilities were summed for each product profile to determine the most preferred treatment.
Based on the results from 161 patients, attributes affecting visual functioning, including improving visual acuity and reducing adverse events (eg, chance of cataracts), were more important than those not directly affecting vision (eg, administration). Overall, 52%, 20%, 17%, and 11% preferred the product profiles matching to the antivascular endothelial growth factor, steroid, focal laser, and panretinal laser therapies. Preferences did not vary substantially by previous treatment experience, age, or type of DR (macular edema, proliferative DR, both or neither), with the exception that more macular edema only patients preferred focal laser over steroid treatment (19% versus 14%, respectively).
When considering the potential effects of treatment over a 1-year period, treatment preferences in DR are most influenced by those that may positively or negatively affect visual functioning.
PMCID: PMC3105876  PMID: 21660105
diabetes; retinopathy; patient preference; ophthalmology; conjoint analysis
7.  Clinical risk factors for age-related macular degeneration: a systematic review and meta-analysis 
BMC Ophthalmology  2010;10:31.
Age-related macular degeneration (AMD) is the leading cause of blindness in Western countries. Numerous risk factors have been reported but the evidence and strength of association is variable. We aimed to identify those risk factors with strong levels of evidence which could be easily assessed by physicians or ophthalmologists to implement preventive interventions or address current behaviours.
A systematic review identified 18 prospective and cross-sectional studies and 6 case control studies involving 113,780 persons with 17,236 cases of late AMD that included an estimate of the association between late AMD and at least one of 16 pre-selected risk factors. Fixed-effects meta-analyses were conducted for each factor to combine odds ratio (OR) and/or relative risk (RR) outcomes across studies by study design. Overall raw point estimates of each risk factor and associated 95% confidence intervals (CI) were calculated.
Increasing age, current cigarette smoking, previous cataract surgery, and a family history of AMD showed strong and consistent associations with late AMD. Risk factors with moderate and consistent associations were higher body mass index, history of cardiovascular disease, hypertension, and higher plasma fibrinogen. Risk factors with weaker and inconsistent associations were gender, ethnicity, diabetes, iris colour, history of cerebrovascular disease, and serum total and HDL cholesterol and triglyceride levels.
Smoking, previous cataract surgery and a family history of AMD are consistent risk factors for AMD. Cardiovascular risk factors are also associated with AMD. Knowledge of these risk factors that may be easily assessed by physicians and general ophthalmologists may assist in identification and appropriate referral of persons at risk of AMD.
PMCID: PMC3009619  PMID: 21144031
8.  Rates of Progression in Diabetic Retinopathy During Different Time Periods 
Diabetes Care  2009;32(12):2307-2313.
This meta-analysis reviews rates of progression of diabetic retinopathy to proliferative diabetic retinopathy (PDR) and/or severe visual loss (SVL) and temporal trends.
This systematic literature review and meta-analysis of prospective studies assesses progression of retinopathy among diabetic patients without treatment for retinopathy at baseline. Studies published between 1975 to February 2008 were identified. Outcomes of interest were rates of progression to PDR and/or SVL. Pooled baseline characteristics and outcome measures were summarized using weighted averages of counts and means. Baseline characteristics and outcomes were compared between two periods: 1975–1985 and 1986–2008.
A total of 28 studies comprising 27,120 diabetic patients (mean age 49.8 years) were included. After 4 years, pooled incidence rates for PDR and SVL were 11.0 and 7.2%, respectively. Rates were lower among participants in 1986–2008 than in 1975–1985. After 10 years, similar patterns were observed. Participants in 1986–2008 studies had lower proportions of PDR and non-PDR at all time points than participants in 1975–1985 studies.
Since 1985, diabetic patients have lower rates of progression to PDR and SVL. These findings may reflect an increased awareness of retinopathy risk factors; earlier identification and initiation of care for patients with retinopathy; and improved medical management of glucose, blood pressure, and serum lipids. Differences in baseline characteristics, particularly in the prevalence and severity of retinopathy, could also have contributed to these temporal differences.
PMCID: PMC2782996  PMID: 19940227
9.  Joint Assessment of Intended and Unintended Effects of Medications: An Example Using Vascular Endothelial Growth Factor Inhibitors for Neovascular Age-Related Macular Degeneration 
Journal of Ophthalmology  2010;2009:540431.
Objective. To estimate the net health benefits of pegaptanib and ranibizumab by considering the impact of visual acuity and unintended effects (cardiovascular and hemorrhagic events) on quality-of-life among persons with neovascular age-related macular degeneration. Methods. We designed a probabilistic decision-analytic model using published data. It employed 17 visual health states and three for unintended effects. We calculated incremental net health benefits by subtracting the harms of each medication from the benefit using the quality-adjusted life year (QALY). Results. In a hypothetical cohort of 1,000 75-year olds with new-onset bilateral age-related macular degeneration followed for ten years, the mean QALYs per patient is 3.7 for usual care, 4.2 for pegaptanib, and 4.3 for ranibizumab. Net benefits decline with increasing baseline rates of unintended effects. Interpretation. Net health benefits present a quantitative, potentially useful tool to assist patients and ophthalmologists in balancing the benefits and harms of interventions for age-related macular degeneration.
PMCID: PMC2836847  PMID: 20339464

Results 1-9 (9)