Does incubation period of COVID-19 vary with age? A study of epidemiologically linked cases in Singapore.

This study estimates the incubation period of COVID-19 among locally transmitted cases, and its association with age to better inform public health measures in containing COVID-19. Epidemiological data of all PCR-confirmed COVID-19 cases from all restructured hospitals in Singapore were collected between 23 January 2020 and 2 April 2020. Activity mapping and detailed epidemiological investigation were conducted by trained personnel. Positive cases without clear exposure to another positive case were excluded from the analysis. One hundred and sixty-four cases (15.6% of patients) met the inclusion criteria during the defined period. The crude median incubation period was 5 days (range 1-12 days) and median age was 42 years (range 5-79 years). The median incubation period among those 70 years and older was significantly longer than those younger than 70 years (8 vis-à-vis 5 days, P = 0.040). Incubation period was negatively correlated with day of illness in both groups. These findings support current policies of 14-day quarantine periods for close contacts of confirmed cases and 28 days for monitoring infections in known clusters. An elderly person who may have a longer incubation period than a younger counterpart may benefit from earlier and proactive testing, especially after exposure to a positive case.

Projecting the Burden of Chronic Kidney Disease in a Developed Country and Its Implications on Public Health.

BACKGROUND: Chronic Kidney Disease (CKD) is a major public health problem worldwide. There is limited literature on a model to project the number of people with CKD. This study projects the number of residents with CKD in Singapore by 2035 using a Markov model. METHODS: A Markov model with nine mutually exclusive health states was developed according to the clinical course of CKD, based on a discrete time interval of 1 year. The model simulated the transition of cohorts across different health states from 2007 to 2035 using prevalence, incidence, mortality, disease transition, and disease detection rates. RESULTS: From 2007 to 2035, the number of residents with CKD is projected to increase from 316,521 to 887,870 and the prevalence from 12.2% to 24.3%. Patients with CKD stages 1-2 constituted the largest proportion. The proportion of undiagnosed cases will decline from 72.1% to 56.4%, resulting from faster progression to higher CKD stages and its eventual detection. CONCLUSION: By 2035, about one-quarter of the Singapore residents are expected to have CKD. National policies need to focus on primary disease prevention and early disease detection to avoid delayed treatment of CKD which eventually leads to end-stage renal disease.

Validity and reliability of a self-reported measure of medication adherence in patients with Type 2 diabetes mellitus in Singapore.

AIMS: A reliable and valid measure is essential for the assessment of medication adherence. Until now, no patient-reported medication adherence measure has been validated in Singapore. The aim of this study was to validate a modified 4-item Morisky-Green-Levine Medication Adherence Scale in patients with Type 2 diabetes in Singapore. METHODS: A cross-sectional survey was conducted in a sample of outpatients with Type 2 diabetes in Singapore from September to December in 2009. Respondents completed either an English or Chinese version of the modified 4-item Morisky-Green-Levine Medication Adherence Scale. The scale scores ranged from 0 to 4, with higher scores indicating better medication adherence. Reliability was assessed using Cronbach's alpha. Content validity was assessed by expert review. Construct validity was examined using factor analysis and hypothesis testing. RESULTS: Of the 294 respondents who completed the modified Morisky-Green-Levine Medication Adherence Scale, 13.3, 21.4, 35.7 and 29.6% had a score of 0-1, 2, 3 and 4, respectively. The internal consistency of the scale was moderate (Cronbach's alpha = 0.62). Principal component analysis showed that the four items loaded onto one factor (eigenvalue = 1.95). Respondents with higher scores were older (P < 0.001), had lower HbA(1c) levels (P < 0.001) and had better adherence to physician-recommended diet (P < 0.001) and physical exercise (P = 0.02). CONCLUSIONS: The psychometric properties of the modified Morisky-Green-Levine Medication Adherence Scale were less than satisfactory. A ceiling effect was observed. The scale may not be an adequate measure to assess medication adherence in patients with Type 2 diabetes in Singapore. Future research could target refining the scale and investigating its use in other patient populations.

Health-related quality of life and glycaemic control in patients with Type 2 diabetes mellitus in Singapore.

AIMS: To investigate the health-related quality of life of patients with diabetes mellitus in Singapore and its associations with diabetes-related characteristics and glycaemic control. METHODS: An interviewer-administered, cross-sectional survey was conducted in a sample of 301 adult diabetes patients under primary care. The survey questionnaire included both a generic health-related quality of life measure, the Euroqol 5-D and a diabetes-specific instrument, the Audit of Diabetes-dependent Quality of Life. Patients' most recent HbA(1c) values were extracted from their medical records. RESULTS: After excluding patients who lacked the 90-day HbA(1c) test result, the final number of responses analysed was 282. Pain/discomfort was the most common complaint among the five Euroqol 5-D domains (by 28.0% of the respondents). Lack of freedom to eat was the Audit of Diabetes-dependent Quality of Life domain with the greatest negative average weighted impact (= -3.8, on a scale of -9 to 3). A significant association was observed between Audit of Diabetes-dependent Quality of Life average weighted impact and both duration of diabetes and use of insulin. A negative correlation was found between health-related quality of life and HbA(1c) values in both health-related quality of life measures (both r=-0.2, P=0.001). CONCLUSIONS: Patients with diabetes in primary-care settings frequently reported problems with pain/discomfort and restrictions in diet. Poorer health-related quality of life was found to be associated with higher HbA(1c) values. The chronicity of diabetes and insulin therapy may have a negative impact on patients' diabetes-related health-related quality of life. This study indicates the importance of achieving better disease management to improve the health-related quality of life of patients with diabetes.

Stratifying healthcare costs using the Diabetes Complication Severity Index.

OBJECTIVE: We aim to determine whether healthcare costs for patients diagnosed with Type 2 Diabetes Mellitus (T2DM) are associated with the severity of diabetes complications as measured by the Diabetes Complication Severity Index (DCSI). METHODS: Retrospective cohort analysis was performed on a 2007 primary care cohort of T2DM patients. The DCSI is a 13-point scale, which comprises 7 categories of complications and their severity levels. Healthcare cost data from 2008 and 2009 were used as primary outcome. Inpatient and outpatient costs incurred for services consumed by patients within the provider network were included. Generalized linear model with log-link and gamma distribution was used to predict healthcare costs. RESULTS: Of the 59,767 T2DM patients, 2977 (5.0%) deaths occurred and 1336 (2.2%) were lost to follow up. Healthcare cost was strongly associated with increase in DCSI score. Compared to patients without complications, those with more complications (higher DCSI score) had an increased risk of higher healthcare costs. Risk ratio (RR) increased from 1.25 (95%CI: 1.19-1.32) for DCSI=1 to 1.61 (1.51-1.72) for DCSI=2; 2.10 (1.91-2.31) for DCSI=3; 2.52 (2.21-2.87) for DCSI=4 and 3.62 (3.09-4.25) for DCSI≥5. As a continuous score, a one-point increase in the DCSI was associated with a cost increase of 27% (95%CI: 1.25-1.29). CONCLUSION: The DCSI score is a useful tool for predicting direct healthcare costs. The DCSI can be used to triage high-risk patients for more focused secondary prevention interventions at primary care level, in a bid to lower overall healthcare costs.

A preliminary evaluation of a disease management programme for patients with diabetes mellitus and hypertension in a primary healthcare setting.

INTRODUCTION: The Comprehensive Chronic Care Programme (CCCP) is an intensified programme designed to provide comprehensive care for the management of diabetes mellitus, hypertension and hyperlipidaemia at a primary healthcare setting. A formative study was done to evaluate the effectiveness of the CCCP compared to the normal polyclinic management of diabetes mellitus. MATERIALS AND METHODS: Control of diabetes (HbA1c) and hypertension (blood pressure) in 63 diabetic patients of a pilot CCCP was compared with 100 diabetic patients not on the programme (non-CCCP) after a 6-month follow-up. Paired t-tests were conducted for differences in mean HbA1c values between baseline and after 6 months. The H-rank test was applied to check for significant differences in change categories of hypertension control between CCCP and non-CCCP cases. RESULTS: In the CCCP group, there was a two-point decrease in HbA1c after 6 months and 65.1% of the patients showed improvement. The proportion of patients achieving optimal diabetic control increased from 9.5% to 36.5%. Conversely, there was deterioration in the non-CCCP group with decrease in the proportion of patients achieving optimal diabetic control from 31% to 21%. Of the hypertensive patients in the CCCP group, 54.5% showed an improvement in blood pressure (BP) control while 44% of the non-CCCP group showed improvement at 6 months. CONCLUSIONS: CCCP, a comprehensive chronic disease management programme, is effective for good diabetic control of patients with diabetes mellitus.