Browsing by Subject "Proxy"

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    Can caregivers report their care recipients' post-stroke hospitalizations and outpatient visits accurately? Findings of an Asian prospective stroke cohort.
    (BMC health services research, 2018-10-25) Tyagi, Shilpa; Koh, Gerald Choon-Huat; Luo, Nan; Tan, Kelvin Bryan; Hoenig, Helen; Matchar, David B; Yoong, Joanne; Finkelstein, Eric A; Lee, Kim En; Venketasubramanian, N; Menon, Edward; Chan, Kin Ming; De Silva, Deidre Anne; Yap, Philip; Tan, Boon Yeow; Chew, Effie; Young, Sherry H; Ng, Yee Sien; Tu, Tian Ming; Ang, Yan Hoon; Kong, Keng He; Singh, Rajinder; Merchant, Reshma A; Chang, Hui Meng; Yeo, Tseng Tsai; Ning, Chou; Cheong, Angela; Ng, Yu Li; Tan, Chuen Seng

    Background

    Health services research aimed at understanding service use and improving resource allocation often relies on collecting subjectively reported or proxy-reported healthcare service utilization (HSU) data. It is important to know the discrepancies in such self or proxy reports, as they have significant financial and policy implications. In high-dependency populations, such as stroke survivors, with varying levels of cognitive impairment and dysphasia, caregivers are often potential sources of stroke survivors' HSU information. Most of the work conducted on agreement analysis to date has focused on validating different sources of self-reported data, with few studies exploring the validity of caregiver-reported data. Addressing this gap, our study aimed to quantify the agreement across the caregiver-reported and national claims-based HSU of stroke patients.

    Methods

    A prospective study comprising multi-ethnic stroke patient and caregiver dyads (N = 485) in Singapore was the basis of the current analysis, which used linked national claims records. Caregiver-reported health services data were collected via face-to-face and telephone interviews, and similar health services data were extracted from the national claims records. The main outcome variable was the modified intraclass correlation coefficient (ICC), which provided the level of agreement across both data sources. We further identified the amount of over- or under-reporting by caregivers across different service types.

    Results

    We observed variations in agreement for different health services, with agreement across caregiver reports and national claims records being the highest for outpatient visits (specialist and primary care), followed by hospitalizations and emergency department visits. Interestingly, caregivers over-reported hospitalizations by approximately 49% and under-reported specialist and primary care visits by approximately 20 to 30%.

    Conclusions

    The accuracy of the caregiver-reported HSU of stroke patients varies across different service types. Relatively more objective data sources, such as national claims records, should be considered as a first choice for quantifying health care usage before considering caregiver-reported usage. Caregiver-reported outpatient service use was relatively more accurate than inpatient service use over shorter recall periods. Therefore, in situations where objective data sources are limited, caregiver-reported outpatient information can be considered for low volumes of healthcare consumption, using an appropriate correction to account for potential under-reporting.
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    Identifying branch-specific positive selection throughout the regulatory genome using an appropriate proxy neutral.
    (BMC genomics, 2020-05-13) Berrio, Alejandro; Haygood, Ralph; Wray, Gregory A
    BACKGROUND:Adaptive changes in cis-regulatory elements are an essential component of evolution by natural selection. Identifying adaptive and functional noncoding DNA elements throughout the genome is therefore crucial for understanding the relationship between phenotype and genotype. RESULTS:We used ENCODE annotations to identify appropriate proxy neutral sequences and demonstrate that the conservativeness of the test can be modulated during the filtration of reference alignments. We applied the method to noncoding Human Accelerated Elements as well as open chromatin elements previously identified in 125 human tissues and cell lines to demonstrate its utility. Then, we evaluated the impact of query region length, proxy neutral sequence length, and branch count on test sensitivity and specificity. We found that the length of the query alignment can vary between 150 bp and 1 kb without affecting the estimation of selection, while for the reference alignment, we found that a length of 3 kb is adequate for proper testing. We also simulated sequence alignments under different classes of evolution and validated our ability to distinguish positive selection from relaxation of constraint and neutral evolution. Finally, we re-confirmed that a quarter of all non-coding Human Accelerated Elements are evolving by positive selection. CONCLUSION:Here, we introduce a method we called adaptiPhy, which adds significant improvements to our earlier method that tests for branch-specific directional selection in noncoding sequences. The motivation for these improvements is to provide a more sensitive and better targeted characterization of directional selection and neutral evolution across the genome.