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Biomedical subjects

B H Heng

Publications and source records attributed to B H Heng.

At least 19 recordsLinked to original sources
PubMed2004

Factors associated with transmission of severe acute respiratory syndrome among health-care workers in Singapore.

Between 1 and 22 March 2003, a nosocomial outbreak of Severe Acute Respiratory Syndrome (SARS) occurred at the Communicable Disease Centre in Tan Tock Seng Hospital, Singapore, the national treatment and isolation facility for patients with SARS. A case-control study with 36 cases and 50 controls was conducted of factors associated with the transmission of SARS within the hospital. In univariate analysis, contact with respiratory secretions elevated the odds ratio to 6.9 (95 % CI 1.4-34.6, P= 0.02). Protection was conferred by hand washing (OR 0.06, 95% CI 0.007-0.5, P=0.03) and wearing of N95 masks (OR 0.1, 95% CI 0.03-0.4, P=0.001). Use of gloves and gowns had no effect. Multivariate analysis confirmed the strong role of contact with respiratory secretions (adjusted OR 21.8, 95 % CI 1.7 274.8, P=0.017). Both hand washing (adjusted OR 0.07, 95 % CI 0.008-0.66, P=0.02) and wearing of N95 masks (adjusted OR 0.1, 95% CI 0.02-0.86, P=0.04) remained strongly protective but gowns and gloves had no effect.

Adult↗
PubMed2004

Atypical SARS in geriatric patient.

We describe an atypical presentation of severe acute respiratory syndrome (SARS) in a geriatric patient with multiple coexisting conditions. Interpretation of radiographic changes was confounded by cardiac failure, with resolution of fever causing delayed diagnosis and a cluster of cases. SARS should be considered even if a contact history is unavailable, during an ongoing outbreak.

Aged↗
PubMed2002

Stroke disease management--a framework for comprehensive stroke care.

Disease management is an approach to patient care that coordinates medical resources for the patient across the entire healthcare delivery system throughout the lifetime of the patient with the disease. Stroke is suitable for disease management as it is a well-known disease with a high prevalence, high cost, variable practice pattern, poor clinical outcome, and managed by a non-integrated healthcare system. It has measurable and actionable outcomes, with available local expertise and support of the Ministry of Health. Developing the programme requires a multidisciplinary team, baseline data on target populations and healthcare services, identification of core components, collaboration with key stakeholders, development of evidence-based clinical practice guidelines and carepaths, institution of care coordinators, use of information technology and continuous quality improvement to produce an effective plan. Core components include public education, risk factor screening and management, primary care and specialist clinics, acute stroke units, inpatient and outpatient rehabilitation facilities, and supportive community services including medical, nursing, therapy, home help and support groups for patients and carers. The family physician plays a key role. Coordination of services is best done by a network of hospital and community-based care managers, and is enhanced by a coordinating call centre. Continuous quality improvement is required, with audit of processes and outcomes, facilitated by a disease registry. Pitfalls include inappropriate exclusion of deserving patients, misuse, loss of physician and patient independence, over-estimation of benefits, and care fragmentation. Collaboration and cooperative among all parties will help ensure a successful and sustainable programme.

Comprehensive Health Care↗
PubMed2001

Implementing chronic disease management in the public healthcare sector in Singapore: the role of hospitals.

The public health care delivery system in Singapore faces the challenges of a rapidly ageing population, an increasing chronic disease burden, increasing healthcare cost, rising expectations and demand for better health services, and shortage of resources. It is also fragmented, resulting in duplication and lack of coordination between institutions. A disease management approach has been adopted by the National Healthcare Group (NHG) as a critical strategy to provide holistic, cost-effective, seamless and well-coordinated care across the continuum. The framework in the development of the disease management plan included identifying the diseases and defining the target population, organizing a multi-disciplinary team lead by a clinician champion, defining the core components, treatment protocols and evaluation methods, defining the goals, and measuring and managing the outcomes. As disease management and case management for chronic diseases are new approaches adopted in the healthcare delivery system, there is a lack of understanding by healthcare professionals. The leadership and participation of hospital physicians was sought in the planning, design and outcomes monitoring to ensure their 'buy-in' and the successful implementation and effectiveness of the program. The episodic diagnosis related group (DRG)-based framework of funding and subvention for healthcare, and the shortage of step-care care facilities, have been recognized by the Ministry of Health as an impediments to the implementation, and these are currently being addressed.

Case Management↗
PubMed1998

Epidemiological surveillance of melioidosis in Singapore.

During the period 1989 to 1996, a total of 372 cases of melioidosis, with 147 deaths, were reported, giving a mean annual incidence rate of 1.7 per 100,000 population and a case-fatality rate of 39.5%. Majority (89%) of the clinical cases were confirmed by culture of Burkholderia pseudomallei, while the others were presumptive cases based on a single blood specimen with an indirect haemaglutination (IHA) antibody titre of > or = 1:16. The highest incidence rate was reported in those aged 45 years and above (5.7 per 100,000 population), males (2.8 per 100,000 population), and Indian ethnic group (3.0 per 100,000 population). Cases were distributed throughout the island all year round. There was no correlation with rainfall. Most of the cases (77.4%) had other concurrent medical conditions, the most common being diabetes mellitus (57.5%). Factors significantly associated with a higher case-fatality rate were age (55 years and above), septicaemia, smoking history and heart or renal failure. The overall case-fatality rate has been declining from 60% in 1989 to 27% in 1996 due to a greater awareness among medical practitioners to diagnose and treat the disease early. The overall seroprevalence of IHA antibody (titre of > or = 1:16) among asymptomatic population groups was 0.2%. B. pseudomallei isolated from clinical specimens were sensitive to imipenem (100%), ceftazidime (99.1%), piperacillin (99.7%), ampicillin-clavulanate (98.5%), minocycline (97.4%), chloramphenicol (94.3%), doxycycline (94.3%) and tetracycline (93.9%). Of 395 samples of soil collected during epidemiological investigation of reported cases, 1.8% were positive for B. pseudomallei.

Adolescent↗
PubMed1997

Comparison of polymerase chain reaction and conventional culture for the detection of legionellae in cooling tower waters in Singapore.

A total of 80 cooling tower water samples were investigated for legionellae using both cultural and polymerase chain reaction (PCR) methods. PCR was performed with the Perkin Elmer EnviroAmp Legionella kit. Forty-seven samples (58.8%) were found positive by both methods; 29 samples (36.3%) were positive by PCR only, while four samples (5%) showed PCR inhibition despite the adoption of the more stringent sample preparation protocol especially designed to eliminate inhibitors.

Air Conditioning↗
PubMed1997

Surveillance of legionellosis and Legionella bacteria in the built environment in Singapore.

During the period 1986 to 1996, a total of 258 sporadic cases of community-acquired legionellosis was reported, giving a mean annual morbidity rate of 0.9 per 100,000 population. Majority of the cases (91.5%) was serologically diagnosed by the indirect fluorescent antibody (IFA) test against Legionella pneumophila based on single sera with a titre of > or = 1:1024. The others were confirmed by a four-fold increase in IFA titre to a minimum of 1:128 (7.4%) and by culture (1.1%). Cases were reported predominantly among males, ethnic Indians, the elderly and those with concurrent medical conditions. The overall case-fatality rate was 14.7%, with the rate significantly higher among those aged > or = 45 years (21%), smokers (20.4%) and those with concurrent medical conditions (22.5%). Seroepidemiological studies among the healthy population based on an IFA titre of > or = 1:32 showed a prevalence of between 10.3% and 21.9%. Of the various occupational groups investigated, high seroprevalence rates were found in foreign construction workers (52.6%) and occupants of a building investigated for an unusual building-related illness (76.1%). Environmental surveillance of Legionella bacteria showed that 36% of cooling towers, 15% to 19% of decorative fountains and waterfalls and 2% of spa pools were positive. The majority (85%) of environmental isolates was identified as Legionella pneumophila: 54.8% of serogroup 1 and 5% of Pontiac subtype.

Adolescent↗
PubMed1996

Gestational diabetes in Singaporean women: use of the glucose challenge test as a screening test and identification of high risk factors.

In this study, 1141 antenatal women attending 9 Government polyclinics were screened between 24 and 28 weeks of gestation for gestational diabetes mellitus (GDM) using the glucose challenge test (GCT). An attempt was made to determine whether 7.2 mmol/l or 7.8 mmol/l was an effective cut-off point as an indicator for GDM. The women with GCT levels of > or = 7.2 mmol/l had an oral glucose tolerance test (OGTT) for confirmation of GDM. The results showed that 420 (36.8%) had GCT levels > or = 7.2 mmol/l, including 299 (26.2%) with GCT levels of > or = 7.8 mmol/l. Of the 190 OGTT carried out, 8 (4.2%) were confirmed to have GDM, all of whom had GCT levels of > or = 7.8 mmol/l, indicating that a GCT level of 7.8 mmol/l was the effective cut-off point. Univariate analysis showed that epidemiological features associated with a raised GCT > or = 7.8 mmol/l were, older age that is 30 years and above, Chinese ethnic group, maternal obesity (body mass index > or = 25) and history of > or = 4 pregnancies. Multivariate analysis using stepwise logistic regression, showed that factors significantly and independently associated with raised GCT levels were older age, Chinese ethnic group and maternal obesity. All antenatal women should be screened for GDM using the GCT, and those with levels of > or = 7.8 mmol/l should be subjected to the OGTT for confirmation.

Adult↗
PubMed1995

Prevalence of hepatitis B virus (HBV) infection in Singapore men with sexually transmitted diseases and HIV infection: role of sexual transmission in a city state with intermediate HBV endemicity.

STUDY OBJECTIVES: To describe the prevalence of hepatitis B virus (HBV) infection in patients with sexually transmitted diseases (STD) and human immunodeficiency virus (HIV) infection, and to determine the role of sexual transmission of HBV infection in Singapore. DESIGN: A cross sectional study of all consecutive men presenting with a new episode of STD at a government outpatient clinic and all men with HIV infection on routine follow up at a government hospital. The prevalence of various HBV markers was compared with that of healthy males aged 15 years and above (controls). SETTING: Singapore, a city state of intermediate HBV endemicity. SUBJECTS: These comprised 497 STD patients, 47 HIV infected patients, and 418 controls. MAIN RESULTS: The overall seroprevalences of HBV infection in STD patients, HIV infected patients, and control subjects were 41.2%, 61.7%, and 33.3%, respectively (p < 0.001). The seroprevalences of hepatitis B surface antigen (6.2%, 8.5%, and 4.5%, respectively) were comparable in the three groups. Using stepwise logistic regression analysis, the adjusted seroprevalences of HBV infection in STD and HIV infected patients were respectively 2.4 times (95% confidence interval (CI), 1.7, 3.3) and 3.3 times (95% CI 1.7, 6.3) higher than in controls. HBV infection rates were higher among Chinese (odds ratio (OR), 1.9; 95% CI 1.6, 3.4) than non-Chinese, and among those aged 25-34 years (OR 2.4; 95% CI 1.6, 3.4), 35-44 years (OR 3.9; 95% CI 2.5, 5.9), and 45+ years (OR 6.2; 95% CI 3.8, 10.2) than in those aged 15-24 years. Sex related factors significantly associated with higher infection rates, independent of age and ethnic group, were reactive VDRL test (OR 2.4; 95% CI 1.2, 4.7), participation in anal intercourse (OR 2.3; 95% CI 1.2, 4.3), and having 10 or more lifetime sexual partners (OR 1.5; 95% CI, 1.0, 2.1). CONCLUSION: The importance of sexual transmission of HBV in an area of intermediate HBV endemicity was confirmed. Patients attending STD clinics should be routinely screened for HBV markers and those found to be seronegative should be strongly advised to be immunised against this virus.

Adolescent↗
PubMed1995

Long-term immunogenicity and efficacy of a reduced dose of plasma-based hepatitis B vaccine in young adults.

A cohort of seronegative preclinical medical and dental students and another cohort of seronegative national service recruits who were immunized intramuscularly with a reduced dose (10 micrograms) of plasma-based hepatitis B vaccine (Merck, Sharp & Dohme) at the start of the study and at 1 month and 6 months thereafter were followed up for 5 years and 6 years, respectively. Among the medical and dental students, antibody to hepatitis B surface antigen (anti-HBs) ( > or = 10 mlU/ml) was detected in 81% of the vaccinees at the end of the 5-year follow-up and the geometric mean titre (GMT) had dropped from 412.6 mlU/ml one year after completion of vaccination to 174.9 mlU/ml after 5 years. Antibody to hepatitis B core antigen (anti-HBc) was detected in 0.4-1.0% of the vaccinees but none was positive for hepatitis B surface antigen (HBsAg) during the follow-up period. Among the national servicemen, the anti-HBs seroconversion rate and GMT were considerably lower than those of the preclinical medical and dental students. At the end of the 6-year follow-up, 55% of the vaccinees were positive for anti-HBs ( > or = 10 mlU/ml) and the GMT had dropped from 80.7 mlU/ml one year after completion of vaccination to 30.4 mlU/ml after 6 years. Anti-HBc was detected in 8 (2.7%) and transient HBs antigenaemia in 2 (0.7%) of 293 vaccinees after 4 years.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

How sexually permissive are Singaporeans?

This paper presents data on two surveys done in 1989 and 1992 that indicated the attitudes of Singaporeans to sexuality. Both surveys revealed that Singaporeans have sexually conservative attitudes and those who have a lower education, are single, above the age of 40, are Malays/Muslims hold more conservative views.

Adolescent↗
PubMed1995

Comparison of multiplex PCR and culture for detection of Legionellae in cooling tower water samples.

We compared multiplex polymerase chain reaction (PCR) and culture for detecting the presence of Legionella pneumophila and Legionella spp in cooling tower water samples. Multiplex PCR was performed after phenol extraction of DNA from the samples. The set of primers for the PCR assay involved the 5S rRNA (Legionella spp) and the mip (macrophage infectivity potentiator gene, specific for L. pneumophila) genes as target sequences for amplification. Both the sensitivity and the specificity of the PCR assay were 100% when the 5S rRNA gene was used as target sequence. Isolation of Legionellae from the samples was observed only with the PCR-positive samples. We propose that PCR be used as a screening test before attempting to culture Legionellae from cooling tower water samples.

Air Conditioning↗
PubMed1994

Blood cadmium levels in non-occupationally exposed adult subjects in Singapore.

Cadmium concentrations in whole blood were measured in subjects with no occupational exposure to cadmium. The study covered 128 males and 150 females from the three main ethnic groups in Singapore (namely Chinese, Malays and Indians). The geometric means (GM) of blood cadmium (CdB) levels of non-smoking males and females were 0.21 microgram/l and 0.26 microgram/l, respectively. Smokers had higher GM CdB levels than non-smokers. Significant ethnic differences were observed in both sexes, with Indian males having the highest GM CdB level of 0.48 microgram/l. Among the females, the Chinese had the highest GM CdB level: 0.33 microgram/l. Differences in dietary habits may have contributed to the observed ethnic differences in blood cadmium levels.

Adolescent↗
PubMed1994

Prevalence of hepatitis A virus infection among sewage workers in Singapore.

To determine whether or not occupational exposure to sewage is associated with a higher seroprevalence of hepatitis A virus (HAV) infection, 600 sewage workers in Singapore were tested for total (IgG and IgM) antibody to HAV by enzyme immunoassay. Using logistic regression with stepwise procedure, the adjusted seroprevalence of sewage workers was 2.2 times higher than that of another non-occupationally exposed population group. Seroprevalence was significantly correlated with age and educational levels, the association being independent of the occupational association. The epidemiological data in the study show that sewage workers have an increased occupational risk of acquiring HAV infection and should be protected by active immunization.

Adult↗
PubMed1994

Epidemiological investigations into an outbreak of building-associated illness in Singapore.

In August 1991, the Ministry of the Environment was informed of the occurrence of illnesses suspected to be related to a modern, multi-story office building. Investigations revealed that 34 of the occupants on two floors of the building had non-specific ailments such as eye, throat or skin irritation which caused acute discomfort but resolved upon leaving the premises. Case-control study identified a number of factors significantly associated with the illness; viz. a personal history of allergy, asthma or sinusitis; a high level of work-related stress; and a lack of thermal comfort. One feature of the affected offices was numerous high partitions which tended to obstruct air movement. Adjustments of central temperature to compensate for complaints of "stuffiness" had resulted in wide fluctuations of temperature and relative humidity. Indoor air quality measurements also revealed high bacterial counts, a condition aggravated by the raised relative humidity and inadequate air movement. The problems gradually resolved following major modifications at the offices and air-handling units. This episode confirmed the need for further studies of building-associated illness in the tropics.

Adult↗
PubMed1993

Seroepidemiology of hepatitis A and hepatitis B virus infection in a Gurkha community in Singapore.

The overall prevalence of hepatitis A virus (HAV) infection among the Gurkhas and their families stationed in Singapore was 83.2%, with antibody to HAV detected in 67 (38.1%) of 176 children under 5 years of age, 121 (76.6%) of 158 children between 5 and 14 years, and 600 (97.9%) of 613 older children and adults over age 15 years. Children born in Singapore (102/223 or 45.7%) had a significantly lower crude prevalence than those born in Nepal (85/110 or 77.3%) (P < 0.000001). The age-adjusted difference in prevalence was also statistically significant (P < 0.001). Susceptible children had a high risk of acquiring HAV infection when they travelled to Nepal. As for hepatitis B virus (HBV) infection, the prevalence of hepatitis B surface antigen (HBsAg) was 2.8%, with a higher rate in males (20/560 or 3.6%) than in females (6/384 or 1.6%). The highest HBsAg prevalence (4/26 or 15.4%) was in young adult Gurkhas 15-19 years of age. No significant difference in the crude prevalence of HBV markers was noted between children born in Singapore (45/224 or 20.1%) and those born in Nepal (19/107 or 17.8%). Even after age adjustment, the difference remained insignificant. The prevalence of HBV markers of children of seropositive parents (27/156 or 17.3%) was not significantly higher than that of seronegative parents (19/131 or 14.5%). Married men had a significantly higher age-adjusted prevalence of infection than unmarried men (45.4% and 32.4%, respectively; P < 0.05). Seropositivity of one spouse was significantly correlated with the seropositivity of the other (P < 0.05), suggesting a role for heterosexual transmission of HBV infection.

Adolescent↗