Drug product dispensing and estimates of use in a general population survey as a signal detection problem.

PURPOSE: Understanding potential bias due to rarity of the outcome is important when monitoring newly approved drugs and drugs with low availability to the general public. Although there is an increasing use of online surveys to investigate health outcomes, the limits of inference due to drug availability have not been studied. The goal of this study was to quantify the relationship between dispensing of prescription drugs and estimates of use in an online general population survey. METHODS: An online repeated, cross-sectional survey from 2018 to 2020 was used to estimate the number of adults in the United States who used prescription drugs in the general population and compared to estimated number of prescriptions dispensed over an equivalent time period. Joinpoint regression was used to quantify thresholds. A sample of respondents was retested to estimate reliability statistics. RESULTS: A model with a single threshold was the best fit, with the estimated threshold of 565 000 (95% CI: 9500-11 600 000) prescriptions dispensed per year. Above the threshold, there was a significant association between dispensing and estimates (p < 0.001); below the threshold, the relationship was not significant (p = 0.912). Above the threshold, responses were more reliable than random chance, and reliability steadily increased with increased dispensing. CONCLUSIONS: These results suggest the threshold demarcates two distinct pharmacoepidemiological paradigms when investigating drug use in general population surveys. Dispensing can be used as a guide to determine the epidemiological paradigm that is best suited.

An Online Survey for Pharmacoepidemiological Investigation (Survey of Non-Medical Use of Prescription Drugs Program): Validation Study.

BACKGROUND: In rapidly changing fields such as the study of drug use, the need for accurate and timely data is paramount to properly inform policy and intervention decisions. Trends in drug use can change rapidly by month, and using study designs with flexible modules could present advantages. Timely data from online panels can inform proactive interventions against emerging trends, leading to a faster public response. However, threats to validity from using online panels must be addressed to create accurate estimates. OBJECTIVE: The objective of this study was to demonstrate a comprehensive methodological approach that optimizes a nonprobability, online opt-in sample to provide timely, accurate national estimates on prevalence of drug use. METHODS: The Survey of Non-Medical Use of Prescription Drugs Program from the Researched Abuse, Diversion and Addiction Related Surveillance (RADARS) System is an online, cross-sectional survey on drug use in the United States, and several best practices were implemented. To optimize final estimates, two best practices were investigated in detail: exclusion of respondents showing careless or improbable responding patterns and calibration of weights. The approach in this work was to cumulatively implement each method, which improved key estimates during the third quarter 2018 survey launch. Cutoffs for five exclusion criteria were tested. Using a series of benchmarks, average relative bias and changes in bias were calculated for 33 different weighting variable combinations. RESULTS: There were 148,274 invitations sent to panelists, with 40,021 who initiated the survey (26.99%). After eligibility assessment, 20.23% (29,998/148,274) of the completed questionnaires were available for analysis. A total of 0.52% (157/29,998) of respondents were excluded based on careless or improbable responses; however, these exclusions had larger impacts on lower volume drugs. Number of exclusions applied were negatively correlated to total dispensing volume by drug (Spearman ρ=-.88, P<.001). A weighting scheme including three demographic and two health characteristics reduced average relative bias by 31.2%. After weighting, estimates of drug use decreased, reflecting a weighted sample that had healthier benchmarks than the unweighted sample. CONCLUSIONS: Our study illustrates a new approach to using nonprobability online panels to achieve national prevalence estimates for drug abuse. We were able to overcome challenges with using nonprobability internet samples, including misclassification due to improbable responses. Final drug use and health estimates demonstrated concurrent validity to national probability-based drug use and health surveys. Inclusion of multiple best practices cumulatively improved the estimates generated. This method can bridge the information gap when there is a need for prompt, accurate national data.

Relationship between Human Immunodeficiency Virus Neuroretinal Disorder and Vision-Specific Quality of Life among People with AIDS.

PURPOSE: Some human immunodeficiency virus (HIV)-infected individuals have evidence of optic nerve or retinal dysfunction that manifests as decreased contrast sensitivity, even with good best-corrected visual acuity (BCVA). This condition, termed HIV-related neuroretinal disorder (HIV-NRD), is a risk factor for vision impairment (BCVA <20/40), blindness (BCVA ≤20/200), and increased mortality. We investigated the effect of HIV-NRD on vision-specific quality of life (QOL). DESIGN: Cross-sectional analysis of data from a prospective, observational study. PARTICIPANTS: Individuals from the Longitudinal Study of the Ocular Complications of AIDS cohort who completed the National Eye Institute 25-item Visual Function Questionnaire (VFQ-25), had BCVA of 20/40 or better, and had no evidence of ocular opportunistic infection or cataract. METHODS: We compared QOL by HIV-NRD status, adjusting for potential confounding variables, using multiple linear regression. Among those with HIV-NRD, we assessed the relationship between VFQ-25 and the logarithm of contrast sensitivity (logCS), using Spearman correlation. We defined a minimum clinically important difference (MCID) as 1 standard error of measurement from a well-characterized, historical population of individuals with a variety of ophthalmic disorders. MAIN OUTCOME MEASURES: Subscales and composite VFQ-25 scores (0 = worst, 100 = best). RESULTS: A total of 813 individuals met study criteria. Those with HIV-NRD (n = 39 [4.8%]) had a lower mean composite score than those without HIV-NRD (81 vs. 89; P = 0.0002) and lower mean scores in the following subscales: near activities (77 vs. 86; P = 0.004), distance activities (85 vs. 91; P = 0.01), social functioning (89 vs. 96; P = 0.0005), mental health (75 vs. 87; P = 0.0001), dependency (81 vs. 94; P < 0.0001), driving (75 vs. 85; P = 0.02), color vision (90 vs. 97; P < 0.0001), and peripheral vision (85 vs. 91; P = 0.0496). Score differences for each of these subscales met criteria for MCID. Among those with HIV-NRD, there was a positive correlation between logCS and composite score (r = 0.36; 95% confidence interval, 0.04-0.60). CONCLUSIONS: HIV-NRD has a statistically significant and clinically meaningful association with decreased vision-specific QOL among people with AIDS and good BCVA.

The prevalence and incidence of epiretinal membranes in eyes with inactive extramacular CMV retinitis.

PURPOSE: To determine the prevalence and incidence of epiretinal membranes (ERM) in eyes with inactive extramacular cytomegalovirus (CMV) retinitis in patients with acquired immune deficiency syndrome (AIDS). METHODS: A case-control report from a longitudinal multicenter observational study by the Studies of the Ocular Complications of AIDS (SOCA) Research Group. A total of 357 eyes of 270 patients with inactive CMV retinitis and 1084 eyes of 552 patients with no ocular opportunistic infection (OOI) were studied. Stereoscopic views of the posterior pole from fundus photographs were assessed at baseline and year 5 visits for the presence of macular ERM. Generalized estimating equations (GEE) logistic regression was used to compare the prevalence and 5-year incidence of ERM in eyes with and without CMV retinitis at enrollment. Crude and adjusted logistic regression was performed adjusting for possible confounders. Main outcome measures included the prevalence, incidence, estimated prevalence, and incidence odds ratios. RESULTS: The prevalence of ERM at enrollment was 14.8% (53/357) in eyes with CMV retinitis versus 1.8% (19/1084) in eyes with no OOI. The incidence of ERM at 5 years was 18.6% (16/86) in eyes with CMV retinitis versus 2.4% (6/253) in eyes with no OOI. The crude odds ratio (OR) (95% confidence interval, CI) for prevalence was 9.8 (5.5-17.5) (P < 0.01). The crude OR (95% CI) for incidence was 9.4 (3.2-27.9) (P < 0.01). CONCLUSIONS: A history of extramacular CMV retinitis is associated with increased prevalence and incidence of ERM formation compared to what is seen in eyes without ocular opportunistic infections in AIDS patients.