Biomedical subjects

Joseph Lau

Publications and source records attributed to Joseph Lau.

83 records · Page 5Linked to original sources

PubMed2002

Standardized retrieval of side effects data for meta-analysis of safety outcomes. A feasibility study in acute sinusitis.

Accurate and complete safety data are indispensable for the proper evaluation of the benefit-to-harm ratio of medical interventions. We evaluated whether a systematic review and meta-analysis of standardized safety data is feasible by requesting information on side effects directly from the investigators of all 38 antibiotic trials on acute sinusitis published in the last decade. We requested standardized information on gastrointestinal toxicity outcomes, including hospitalizations, discontinuations, and days with nausea/vomiting, diarrhea, or both. Responses were received only for 16 trials (42%), and safety data were contributed only for 9 trials (24%). In some trials, safety data had not been collected, had been lost, or had been transferred to other companies. The odds of data retrieval was higher in general medical journals (P =.024) and independently improved with an increase in sample size (P =.064). The available information suggested side effects may equal or exceed in severity the marginal treatment benefits. Interpretation of safety data was further complicated by heterogeneity or lack of information of use of concomitant drugs, mode of collection of safety information, use of blinding, and other study design parameters. Availability of standardized information for performing meta-analysis of safety data may be limited. Standardized reporting, prospective collection, and long-term availability of safety information should be improved.

Acute Disease↗

PubMed2002

Is primary angioplasty for some as good as primary angioplasty for all?

OBJECTIVES: To investigate whether proper patient selection might allow most of the benefits of population-wide primary coronary angioplasty to be captured in a subgroup of high-risk patients. BACKGROUND: Despite growing evidence that angioplasty yields better outcomes, thrombolytic therapy remains the most common form of reperfusion therapy in acute myocardial infarction (AMI) because of limited capacity for primary coronary angioplasty at most hospitals. METHODS: We used a validated logistic regression model, based on individual patient characteristics, to estimate the distribution of mortality risk in a community-based sample of 1,058 patients who received reperfusion therapy for AMI. To estimate the benefits across different baseline risks, we examined the results of 10 randomized controlled trials using meta-regression techniques. RESULTS: Assuming a constant relative risk reduction, 68% of all mortality benefits in our community-based patient sample could be captured by treating only those patients in the highest quartile of mortality risk and 87% of the benefit could be captured by treating those in the highest half. Moreover, meta-regression of the results from the 10 clinical trials suggests that patients with a mortality risk of less than 2% may be unlikely to receive any mortality benefit. With this risk-benefit relationship, treatment of only the 39% of patients with the highest risk would yield equivalent mortality outcomes to population-wide angioplasty. CONCLUSION: Most of the incremental benefits of primary angioplasty can be achieved by treating high-risk patients. For these patients, thrombolytic therapy may be difficult to justify if nearby primary angioplasty is available. For most patients, however, thrombolytic therapy appears to be an effective alternative.

Adult↗

PubMed2002

Visual acuity and quality of life outcomes in cataract surgery patients in Hong Kong.

BACKGROUND: Visual acuity, visual functioning, and vision related quality of life outcomes after cataract surgery were assessed in a population based study in a suburban area of Hong Kong. METHODS: A cluster sampling design was used to select apartment buildings within housing estates for enumeration. All enumerated residents 60 years of age or over were invited for an eye examination and visual acuity measurement at a site within each estate. Visual functioning (VF) and vision related quality of life (QOL) questionnaires were administered to interview subjects who had undergone cataract surgery and to unoperated people with presenting visual acuity less than 6/60 in either eye, and a sample of those with normal visual acuity. RESULTS: 36.6% of the 310 cataract operated individuals had presenting visual acuity 6/18 or better in both eyes, and 40.0% when measured by pinhole. 4.5% were blind, with presenting visual acuity less than 6/60 in both eyes. Of operated eyes, 59.6% presented with visual acuity 6/18 or better. 11.2% of the operated eyes were blind with vision less than 6/60. Visual acuity outcomes 6/18 or better were marginally associated with surgery in private versus public hospitals. Lens status (pseudophakic versus aphakic) and surgical period (within the most recent 3 years versus before) were not significantly related to vision outcomes. Mean VF and QOL scores decreased consistently with decreasing vision status. Spearman correlation with vision status was 0.420 for VF scores and 0.313 for QOL scores. Among VF/QOL subscales, correlation was strongest for visual perception (r = 0.447) among VF subscales and weakest for self care (r = 0.171) among QOL subscales. Regression adjusted VF and QOL total scores for cataract operated individuals were slightly lower than for those of visually comparable unoperated individuals (p<0.05). CONCLUSIONS: Cataract operations in Hong Kong did not consistently produce good presenting visual acuity outcomes, suggesting that postoperative monitoring would be useful to minimise visual impairment in this population. Although vision outcomes were consistently correlated with all VF/QOL subscale scores, there was a differential impact with VF subscales usually being affected more by reduced acuity than the more general QOL subscales.

Aged↗

PubMed2002

Prevalence of visual impairment, blindness, and cataract surgery in the Hong Kong elderly.

BACKGROUND: The prevalence of vision impairment, unilateral/bilateral blindness, and cataract surgery were estimated in a population based survey among the elderly in a suburban area of Hong Kong. METHODS: 15 public, private, and home ownership scheme housing estates in the Shatin area of Hong Kong were subjected to cluster sampling to randomly select a cross section of people 60 years of age or older. Visual acuity measurements and ocular examinations were conducted at a community site within each estate. The principal cause of reduced vision was identified for eyes with presenting visual acuity worse than 6/18. RESULTS: A total of 3441 subjects from an enumerated population of 4487 (76.7%) completed an eye examination. The prevalence of presenting visual acuity less than 6/18 in at least one eye was 41.3%; and 73.1% in those 80 years of age or older. Unilateral blindness (acuity <6/60) was found in 7.9% of subjects and bilateral blindness in 1.8%. Refractive error and cataract were, respectively, the main causes of vision impairment and blindness. Visual impairment with either eye <6/18 increased with advancing age and was more prevalent in males, the less educated, and those living in public housing estates. The prevalence of cataract surgery was 9.1% and was associated with advancing age and less education. CONCLUSIONS: Blindness and visual disability were common in this socioeconomically advanced population, with most of it easily remedied. Because of a rapidly ageing population, healthcare planners in Hong Kong must prepare for an increasing burden of visual disability and blindness.

Age Distribution↗

PubMed2002

Does acupuncture improve motor recovery after stroke? A meta-analysis of randomized controlled trials.

BACKGROUND AND PURPOSE: Acupuncture may be a promising treatment for poststroke paralysis. We conducted a meta-analysis, assessing the efficacy of acupuncture with and without stroke rehabilitation. METHODS: We identified randomized trials comparing acupuncture with no acupuncture within 6 months of stroke by searching MEDLINE, CINAHL, EMBASE, Cochrane Library, and Chinese medical literature databases. Two reviewers independently extracted data on study characteristics, patient characteristics, and impairment and disability outcomes. The outcome measures were internationally recognized or nationally approved. The fixed- and random-effects models were used to combine effect size and odds ratio across studies. RESULTS: Fourteen trials with 1213 patients met all the inclusion criteria. For the comparison of acupuncture with no acupuncture in addition to stroke rehabilitation, the pooled random-effects estimates of the change in motor impairment and disability were 0.06 (95% CI, -0.12 to 0.24) and 0.49 (95% CI, 0.03 to 0.96), respectively, with heterogeneity in disability measures (P=0.05, chi(2) test). For the comparison of real with sham acupuncture, the pooled random-effects estimate of the change in disability was 0.07 (95% CI, -0.34 to 0.48). For the comparison of acupuncture with no acupuncture without stroke rehabilitation, the pooled random-effects estimate of the change in motor impairment was 0.46 (95% CI, -0.20 to 1.12), and the pooled random-effects odds ratio for disability was 12.5 (95% CI, 4.3 to 36.2), with no statistically significant heterogeneity (P=0.97 and P=0.12, respectively, chi(2) test), but the study quality was poor. CONCLUSIONS: This meta-analysis suggests that with stroke rehabilitation, acupuncture has no additional effect on motor recovery but has a small positive effect on disability, which may be due to a true placebo effect and varied study quality. The efficacy of acupuncture without stroke rehabilitation remains uncertain, mainly because of the poor quality of such studies.

Acupuncture Therapy↗

PubMed2002

Improving safety reporting from randomised trials.

Randomised clinical trials offer a unique opportunity for capturing safety information under a controlled setting that minimises biases in the comparison of different therapeutic options. Nevertheless, empirical evidence across diverse medical fields suggests that the reporting of safety information in clinical trials is largely neglected and receives less attention compared with efficacy outcomes. An analysis of 192 randomised trials has shown that reasons for withdrawals due to toxicity were specified per study arm in only 46% of the trial reports. Adequate reporting of clinical adverse effects and laboratory-determined toxicity occurred in only 39 and 29% of the trials, respectively, even with lenient definitions of what constitutes adequate reporting. The use of standardised scales for adverse effects is a prerequisite for improved reporting on safety in randomised trials. Safety data need to be collected and analysed in a systematic fashion and active surveillance for toxicity during the conduct of a randomised trial is preferable to passive surveillance. Standardised reporting of safety data does not necessarily require extensive space to accomplish. It is essential to provide numerical data per study arm on each type of adverse effect along with a categorisation of the severity of the adverse effects with an emphasis on severe and life-threatening reactions. The severity grading must be referred to well-known standardised scales and new scales need to be carefully defined. Information on withdrawals due to toxicity is also important to report, along with the specific reasons leading to discontinuation. Tabulation of information may be helpful and rare or not previously reported adverse effects should be described in detail. The availability of newer options such as electronic publication, publication of raw databases, large database research, meta-analytic approaches, and prospective registration of clinical trials and of their databases may further improve the safety insights we can gain from randomised clinical trials.

Adverse Drug Reaction Reporting Systems↗

PubMed2002

Self-management education for adults with type 2 diabetes: a meta-analysis of the effect on glycemic control.

OBJECTIVE: To evaluate the efficacy of self-management education on GHb in adults with type 2 diabetes. RESEARCH DESIGN AND METHODS: We searched for English language trials in Medline (1980-1999), Cinahl (1982-1999), and the Educational Resources Information Center database (ERIC) (1980-1999), and we manually searched review articles, journals with highest topic relevance, and reference lists of included articles. Studies were included if they were randomized controlled trials that were published in the English language, tested the effect of self-management education on adults with type 2 diabetes, and reported extractable data on the effect of treatment on GHb. A total of 31 studies of 463 initially identified articles met selection criteria. We computed net change in GHb, stratified by follow-up interval, tested for trial heterogeneity, and calculated pooled effects sizes using random effects models. We examined the effect of baseline GHb, follow-up interval, and intervention characteristics on GHb. RESULTS: On average, the intervention decreased GHb by 0.76% (95% CI 0.34-1.18) more than the control group at immediate follow-up; by 0.26% (0.21% increase - 0.73% decrease) at 1-3 months of follow-up; and by 0.26% (0.05-0.48) at > or = 4 months of follow-up. GHb decreased more with additional contact time between participant and educator; a decrease of 1% was noted for every additional 23.6 h (13.3-105.4) of contact. CONCLUSIONS: Self-management education improves GHb levels at immediate follow-up, and increased contact time increases the effect. The benefit declines 1-3 months after the intervention ceases, however, suggesting that learned behaviors change over time. Further research is needed to develop interventions effective in maintaining long-term glycemic control.

Adaptation, Psychological↗

PubMedDate not supplied

Dialysis membrane and modality in acute renal failure: understanding discordant meta-analyses.

Meta-analyses of the published literature are increasingly being used, allowing similar clinical trials to be combined quantitatively, thereby increasing the precision of the estimation of treatment effect. Four meta-analyses were recently published comparing the impact of dialysis membranes or dialysis modality on clinical outcomes of patients with acute renal failure (ARF) requiring renal replacement therapy. Two studies compared dialysis membranes in intermittent hemodialysis (IHD) and two studies compared continuous renal replacement therapy (CRRT) to IHD. The findings between each pair of meta-analyses were discordant. This was due in part to the differences among meta-analyses in inclusion and exclusion criteria, the paucity of randomized controlled trials, variation in individual study quality, and heterogeneity in the study populations and settings. Understanding these issues is important to properly interpret results from these meta-analyses.

Acute Kidney Injury↗

PubMedDate not supplied

Defining the therapeutic role of local anesthetic sympathetic blockade in complex regional pain syndrome: a narrative and systematic review.

OBJECTIVE: There is growing controversy on the value of blocking the sympathetic nervous system for the treatment of complex regional pain syndromes (CRPS). The authors sought to evaluate the efficacy of sympathetic blockade with local anesthetic in these syndromes. In addition, they performed a comprehensive review of the pathophysiology and other treatments for CRPS. DESIGN: Systematic review of the literature was performed. MEDLINE was searched from 1966 through 1999. The authors identified only three randomized controlled trials (RCTs) that evaluated sympathetic blockade with local anesthetic, but because of differences in study design they were unable to pool the study data. The authors therefore included nonrandomized studies and case series. INTERVENTIONS: Studies were included if local anesthetic sympathetic blockade was used in at least 10 patients. Studies were excluded if continuous infusion techniques, somatic nerve blocks, or combined sympatholytic therapies were evaluated. OUTCOME MEASURES: Pain relief was classified as full, partial, or absent. The lack of a comparison group in the studies allowed only the calculation of distribution of the response categories, and the sum of the pooled rates does not equal 100%. RESULTS: Twenty-nine studies were included that evaluated 1,144 patients. Nineteen studies were retrospective, 5 prospective case series, 3 RCTs, and 2 nonrandomized controlled studies. The quality of the publications was generally poor. Twenty-nine percent of patients had full response, 41% had partial response, and 32% had absent response. It was not possible to estimate the duration of pain relief. CONCLUSIONS: This review raises questions as to the efficacy of local anesthetic sympathetic blockade as treatment of CRPS. Its efficacy is based mainly on case series. Less than one third of patients obtained full pain relief. The absence of control groups in case series leads to an overestimation of the treatment response that can explain the findings.

Complex Regional Pain Syndromes↗

PubMedDate not supplied

A cost comparison of management of chronic hepatitis B and its associated complications in Hong Kong and Singapore.

GOALS: To estimate and compare the direct medical cost in the management of chronic hepatitis B (CHB) infection and its complications from the perspective of public health organizations in Hong Kong and Singapore. BACKGROUND: Hong Kong and Singapore are endemic hepatitis B virus areas with about 10% and 5%, respectively, of the population estimated as hepatitis B virus infected. STUDY: The medical histories of 660 patients with CHB who received medical services over 5 years from three major public hospitals in Hong Kong and Singapore were studied retrospectively. Costs were analyzed according to the five disease states and estimated in Hong Kong dollars (HKD) and Singapore dollars (SGD). RESULTS: In both Hong Kong and Singapore, the per-patient total annual cost increased with the severity of the disease. CHB cost HKD 6318 (US 810 dollars) in Hong Kong and SGD 718.15 (US 410.37 dollars) in Singapore. Compensated cirrhosis cost HKD 10,304 (US 1321 dollars) in Hong Kong and SGD 1,175.34 (US 671.62 dollars) in Singapore. Decompensated cirrhosis cost HKD 58,428 (US 7490 dollars) in Hong Kong and SGD 15,389.84 (US 8794.19 dollars) in Singapore. Hepatocellular carcinoma cost HKD 121,822 (US 15,618 dollars) in Hong Kong and SGD 12314.04 (US 7036.59 dollars) in Singapore. Each case of liver transplant was estimated to cost HKD 514,498 (US 65,961 dollars) in Hong Kong and SGD 86,369.28 (US 49,353.87 dollars) in Singapore. CHB in Hong Kong accounted for about 4% of the healthcare expenditure. CONCLUSION: This study confirms that CHB and its liver disease complications are a significant economic burden to the healthcare budgets of Hong Kong and Singapore, and indicates that effective therapy that arrests or reverses the progression of liver disease would be highly cost-effective.

Adolescent↗

PubMedDate not supplied

Insulin therapy and in-hospital mortality in critically ill patients: systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: Hyperglycemia is common in critically ill hospitalized patients and has been associated with adverse outcomes, including increased mortality. In this review, we examine the effect of insulin therapy on mortality in critically ill patients. METHODS: We updated our previous systematic review and meta-analysis to include recently published trials that report data on the effect of insulin therapy initiated during hospitalization on mortality in adult patients with a critical illness. We also include a short primer on the methods of systematic reviews and meta-analyses, outlining the specific steps and challenges of this methodology. We performed an electronic search in the English language of MEDLINE and the Cochrane Controlled Clinical Trials Register and a hand search of key journals and relevant review articles for randomized controlled trials that reported mortality data on critically ill hospitalized adult patients treated with insulin (regardless of method of administration). RESULTS: We identified 38 relevant studies that entered the analysis. We found that therapy with insulin in adult patients hospitalized for a critical illness, other than hyperglycemic crises, may decrease mortality in certain groups of patients. The beneficial effect of insulin was evident in the surgical intensive care unit (relative risk [RR], 0.58; confidence interval [CI], 0.22-0.62) and in patients with diabetes (RR, 0.76; CI, 0.62-0.92). There was a trend toward benefit in patients with acute myocardial infarction (RR, 0.89; CI, 0.76-1.03). Targeting euglycemia appears to be the main determinant of the benefit of insulin therapy (RR, 0.73; CI, 0.57-0.94). CONCLUSIONS: Insulin therapy in adult patients hospitalized for a critical illness, other than hyperglycemic crises, may decrease mortality in certain groups of patients.

Blood Glucose↗