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Open Access Publications from the University of California

Scholarly Works (144 results)

  • Thesis
  • Peer Reviewed
UC San Francisco Electronic Theses and Dissertations (2018)

Background: Diarrhea is a leading cause of death among children under five globally. Most studies of pediatric diarrhea rely on caregiver-reported stool consistency and frequency to define disease.

Methods: We collected stool samples from 2398 children participating in two water-improvement intervention trials in the Amhara region of Ethiopia. In the smaller trial we examined the pediatric enteric virome across stool consistency to evaluate differences in species richness and community composition using metagenomic sequencing. We also measured caregiver-reported pediatric diarrhea as an outcome for this trial, and performed bias analysis to estimate the impact of misclassified diarrhea on the trial outcome. The consistency of each stool sample was graded by the child’s caregiver and two trained laboratory technicians according to an illustrated stool consistency scale. We assessed the reliability of graded stool consistency among the technicians, then compared the caregiver’s grade to the first technician’s grade. Caregivers were asked to report if children had three or more loose or watery stools in a 24-hour period anytime in the past seven days.

Results: The sensitivity of caregiver-reported loose or watery stool was 15.5 [95 CI: 9.7, 24.2] and the specificity was 98.4 [95CI 97.1, 99.1]. Species richness was highest in watery-consistency stool and decreased as stool consistency became firmer (Spearman's r=-0.45, p=0.013). The greatest differential abundance comparing loose or watery to formed stool was for norovirus GII (7.64, 95 CI 5.8, 9.5) followed by aichivirus A (5.93, 95 CI 4.0, 7.89) and adeno-associated virus 2 (5.81, 95CI 3.9, 7.7).

Conclusions: Caregiver reported stool consistency using the terms ‘loose or watery’ does not accurately describe stool consistency as graded by trained laboratory technicians. Given the predominance of using caregiver-reported stool consistency to define diarrheal disease, the low sensitivity identified in this study suggests that the burden of diarrheal disease may be underestimated and intervention effects could be biased. We documented a difference in pediatric enteric virome according to mBSFS-C stool consistency category. Bias analysis did not reveal a corrected protective effect of the water-improvement intervention.

    Cover page: Defining Diarrhea: Validating and improving caregiver-reported stool consistency as a measure of pediatric diarrhea in the Amhara region of Ethiopia
    • Article
    • Peer Reviewed
    UC San Francisco Previously Published Works (2020)
    In a cross-sectional retrospective study of 3120 diabetic patients aged ≥ 60 years, those taking metformin were less likely to have age-related macular degeneration compared with those not taking the drug (OR 0.70, 95%CI 0.55-0.88).
      Cover page: Relationship between Oral Metformin Use and Age-Related Macular Degeneration
      • Article
      • Peer Reviewed
      UC San Francisco Previously Published Works (2023)

      Objective

      The objective of this scoping review is to understand the extent and type of evidence in relation to telemedicine imaging devices for cornea and external segment conditions.

      Introduction

      The coronavirus pandemic has emphasized the benefits of telemedicine in diagnosing and managing ocular diseases. With the rapid advancement of technology in slit lamp biomicroscopes, smartphones and other ocular surface imaging modalities, telemedicine applications for cornea and external diseases have become an active area of research.

      Inclusion criteria

      For studies to be included, they had to discuss the concept of imaging devices for cornea and external diseases in the context of telemedicine. There was no restriction on the studied population or participants.

      Methods

      A scoping review was conducted according to an a priori protocol. Documents written in English were identified from the PubMed and Embase databases and searches. Anterior segment imaging devices were then classified into different categories.

      Results

      Anterior segment imaging devices identified in this review included 19 slit lamp-based devices, 17 smartphone-based devices and 15 other devices. These tools can detect a wide variety of cornea and external diseases (e.g., pterygium, conjunctivitis, corneal opacity, corneal ulcer, and blepharitis). Fewer than half of the devices (24/51) were assessed for diagnostic performance. Their diagnostic accuracy varied greatly from condition to condition and from device to device. The inter-rater reliability of different photo-graders assessing images was assessed in only a few studies.

      Conclusions

      Anterior segment imaging devices are promising tools for remote diagnosis and management of patients with cornea and external disease. However, there are significant gaps in the literature regarding the diagnostic accuracy and inter-rater reliability of several devices. Future research with rigorous methods is required to validate the use of these devices in telemedicine settings.
        Cover page: Telemedicine for Cornea and External Disease: A Scoping Review of Imaging Devices
        • Article
        • Peer Reviewed
        UC San Francisco Previously Published Works (2017)
        Conjunctivitis is the most common ocular condition diagnosed in US emergency departments (EDs), accounting for almost one-third of all eye-related encounters. Because of its generally nonemergent nature, understanding the burden and timing of conjunctivitis may allow preemptive triage to a less expensive health care setting.
          Cover page: Epidemiology of Conjunctivitis in US Emergency Departments
          • Article
          • Peer Reviewed
          UC San Francisco Previously Published Works (2018)

          Objective

          To assess the current opinion and practice patterns from cornea experts regarding the benefit of corneal cross-linking (CXL) for infectious keratitis (IK).

          Methods and analysis

          An international survey was distributed to corneal specialists via an internet survey. The survey data collected were analysed with descriptive statistics.

          Results

          A survey was sent to 190 recipients, and 29 (15%) respondents completed the survey with an average of 7 years' experience using CXL. A majority of respondents (66%) used CXL to treat IK due to bacterial, fungal, protozoan or unknown aetiology. Main indications to use CXL as adjuvant therapy were worsening infiltrate diameter or depth despite therapy (74%), followed by antibiotic resistance (68%), corneal thinning (53%), poor compliance with medication (26%) and other reasons (21%). Most respondents felt CXL would be at least moderately helpful as an adjuvant therapy for bacterial (96%) or fungal (75%) keratitis; about half (46%) thought it would be helpful for acanthamoeba keratitis. As sole therapy, fewer respondents believed CXL would be at least moderately helpful to treat bacterial (75%), fungal (58%) and acanthamoeba (43%) keratitis.

          Conclusion

          The survey offered insights into current expert practices and opinions of using CXL as therapy for IK. The results of this survey serve to guide in the design of future clinical studies.
            Cover page: Expert practice patterns and opinions on corneal cross-linking for infectious keratitis.
            • Article
            • Peer Reviewed
            UC San Francisco Previously Published Works (2020)
            Recent evidence indicates mass drug administration with azithromycin may reduce child mortality. This study uses verbal autopsy (VA) to investigate the causes of individual deaths during the Macrolides Oraux pour Réduire les Décès avec un Oeil sur la Résistance (MORDOR) trial in Malawi. Cluster randomization was performed as part of MORDOR. Biannual household visits were conducted to distribute azithromycin or placebo to children aged 1-59 months and update the census to identify deaths for VA. MORDOR was not powered to investigate mortality effects at individual sites, but the available evidence is presented here for hypothesis generation regarding the mechanism through which azithromycin may reduce child mortality. Automated VA analysis was performed to infer the likely cause of death using two major analysis programs, InterVA and SmartVA. A total of 334 communities were randomized to azithromycin or placebo, with more than 130,000 person-years of follow-up. During the study, there were 1,184 deaths, of which 1,131 were followed up with VA. Mortality was 9% lower in azithromycin-treated communities than in placebo communities (rate ratio 0.91 [95% CI: 0.79-1.05]; P = 0.20). The intention-to-treat analysis by cause using InterVA suggested fewer HIV/AIDS deaths in azithromycin-treated communities (rate ratio 0.70 [95% CI: 0.50-0.97]; P = 0.03) and fewer pneumonia deaths (rate ratio 0.82 [95% CI: 0.60-1.12]; P = 0.22). The use of the SmartVA algorithm suggested fewer diarrhea deaths (rate ratio 0.71 [95% CI: 0.51-1.00]; P = 0.05) and fewer pneumonia deaths (rate ratio 0.58 [95% CI: 0.33-1.00]; P = 0.05). Although this study is not able to provide strong evidence, the data suggest that the mortality reduction during MORDOR in Malawi may have been due to effects on pneumonia and diarrhea or HIV/AIDS mortality.
              Cover page: Effect of Mass Treatment with Azithromycin on Causes of Death in Children in Malawi: Secondary Analysis from the MORDOR Trial
              • Article
              • Peer Reviewed
              UC San Francisco Previously Published Works (2020)
              The recent Macrolides Oraux pour Réduire les Décès avec un Oeil sur la Résistance (MORDOR) trial reported a reduction in child mortality following biannual azithromycin mass drug administration (MDA). Here, we investigate the financial costs and cost-effectiveness from the health provider perspective of azithromycin MDA at the MORDOR-Malawi study site. During MORDOR, a cluster-randomized trial involving biannual azithromycin MDA or placebo to children aged 1-59 months, fieldwork-related costs were collected, including personnel, transport, consumables, overheads, training, and supervision. Mortality rates in azithromycin- and placebo-treated clusters were calculated overall and for the five health zones of Mangochi district. These were used to estimate the number needed to treat to avert one death and the costs per death and disability-adjusted life year (DALY) averted. The cost per dose of MDA was $0.74 overall, varying between $0.63 and $0.94 in the five zones. Overall, the number needed to treat to avert one death was 1,213 children; the cost per death averted was $898.47, and the cost per DALY averted was $9.98. In the three zones where mortality was lower in azithromycin-treated clusters, the number needed to treat to avert one death, cost per death averted, and cost per DALY averted, respectively, were as follows: 3,070, $2,899.24, and $32.31 in Monkey Bay zone; 1,530, $1,214.42, and $13.49 in Chilipa zone; and 344, $217.98, and $2.42 in Namwera zone. This study is a preliminary cost-effectiveness analysis that indicates azithromycin MDA for reducing child mortality has the potential to be highly cost-effective in some settings in Malawi, but the reasons for geographical variation in effectiveness require further investigation.
                Cover page: Cost-Effectiveness of Mass Treatment with Azithromycin for Reducing Child Mortality in Malawi: Secondary Analysis from the MORDOR Trial
                • Article
                • Peer Reviewed
                UC San Francisco Previously Published Works (2017)

                Purpose

                To assess the relationship between corneal thinning measured by clinician-graded slit-lamp examination compared with ultrasound pachymetry (USP), anterior segment optical coherence tomography (AS-OCT), and the Pentacam.

                Methods

                Patients with corneal thinning underwent USP, AS-OCT, Pentacam measurements and standardized clinical grading by 2 cornea specialists estimating thinning on slit-lamp examination. Reproducibility of each testing modality was assessed using the intraclass correlation coefficient. Bland-Altman plots were used to determine precision and limits of agreement (LOA) between imaging modalities and clinical grading.

                Results

                We included 22 patients with corneal thinning secondary to infectious or inflammatory keratitis. Mean percent stromal thinning estimated by grader 1 was 51% (SD 31) and grader 2 was 49% (SD 33). The intraclass correlation coefficient between the masked examiners was 0.95 (95% confidence interval, 0.88-0.98). Graders were more similar to each other than to any other modality with 2% difference and 4.6% of measurements outside the LOA. When measuring the area of maximum thinning, AS-OCT measured approximately 10% thicker than human graders while the Pentacam measured approximately 10% thinner than human graders with 16.7% outside the LOA. USP measured approximately 20% thinner than human graders with 5.6% outside the LOA.

                Conclusions

                Trained corneal specialists have a high degree of agreement in location and degree of corneal thinning when measured in a standardized fashion on the same day. Other testing modalities had acceptable reproducibility and agreement with clinical examination and each other, although Scheimpflug imaging fared worse for corneal thinning, particularly in the periphery, than the other modalities.
                  • Article
                  • Peer Reviewed
                  UC San Francisco Previously Published Works (2018)

                  Purpose

                  To determine whether ocular trauma occurs more frequently in the summer months.

                  Design

                  Retrospective, cross-sectional study.

                  Methods

                  The Nationwide Emergency Department Sample (NEDS) is a large, publicly available administrative database that provides nationally representative estimates of emergency department (ED) visits in the United States. Billing codes from NEDS from 2006 to 2013 were used to identify all cases of ocular trauma, and the United States decennial census was used to estimate the population at risk for visiting an ED. The main outcome measures were the seasonal and annual trends in the incidence of ED-diagnosed eye trauma.

                  Results

                  Eye trauma was the primary diagnosis for an estimated 5 615 532 ED encounters over the 8-year study period. Those with an eye trauma encounter were predominantly male (66%) and under 60 years of age (91%). The most common ocular trauma presentations were superficial injury of eye and adnexa (101 ED-diagnosed cases per 100 000 population), extraocular foreign body (54 per 100 000 population), contusion of eye and adnexa (27 per 100 000 population), and ocular adnexal open wound (26 per 100 000 population). Each exhibited a statistically significant annual cycle, with a mean annual peak between May and July (P < .01 for each, Edwards test). Eye trauma visits decreased by an average of 4% per year over the study period, with a similar pattern of decline during each calendar month (incidence rate ratio 0.96, 95% confidence interval 0.94-0.98).

                  Conclusions

                  Eye trauma, although decreasing in incidence, is a seasonal condition. Prevention efforts would likely be most effective if implemented in the spring or summer months. Further study to identify other individual-level or regional-level factors that would most benefit from public health efforts is warranted.
                    Cover page: Ocular Injury in United States Emergency Departments: Seasonality and Annual Trends&nbsp;Estimated from a Nationally Representative Dataset
                    • Article
                    • Peer Reviewed
                    UC San Francisco Previously Published Works (2017)

                    Purpose

                    To describe the indications, visual acuity outcomes, and graft survival after penetrating keratoplasty (PKP) in Addis Ababa, Ethiopia.

                    Methods

                    The medical records of patients who underwent PKP at Menelik II Hospital between September 2000 and September 2013 were retrospectively reviewed. The prespecified outcomes were graft survival, visual acuity, and complication rates.

                    Results

                    A total of 321 patients underwent PKP during the study period and were included in the analysis. Indications for surgery were trachoma or leukoma in 141 (44%), keratoconus in 45 (14%), corneal dystrophy in 46 (14%), pseudophakic or aphakic bullous keratopathy in 28 (9%), trauma in 27 (8%), previous graft failure in 18 (6%), active ulcer, burn, or perforation in 9 (3%), and others in 7 (2%). The graft survival rate was 80% overall at 2 years but varied considerably depending on the indication for surgery. Uncorrected visual acuity improved from baseline mean logarithm of the minimum angle of resolution 2.09 (SD 0.67) to mean logarithm of the minimum angle of resolution of 1.53 (SD 1.03) at 2 years. A number of factors affected the visual acuity outcomes. Patients were not routinely refracted, and only 18% (N = 60) of patients had access to corrective spectacles or contact lenses postoperatively. Complication rates were high with infectious keratitis being the most common.

                    Conclusions

                    PKP is becoming a viable treatment for corneal opacity in developing countries. However, the high burden of disease and lack of corrective lenses remain significant obstacles to overcome.
                      Cover page: Penetrating Keratoplasty at a Tertiary Referral Center in Ethiopia
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