Surveillance of childhood diarrhoeal disease in Hong Kong, using standardized hospital discharge data

Enteric Bacteria Isolated from Diarrheal Patients in Korea in 2014

OBJECTIVES

The aim of this study was to characterize the pathogens responsible for causing diarrhea according to season, region of isolation, patient age, and sex as well as to provide useful data for the prevention of diarrheal disease.

METHODS

Stool specimens from 14,886 patients with diarrhea were collected to identify pathogenic bacteria from January 2014 to December 2014 in Korea. A total of 3,526 pathogenic bacteria were isolated and analyzed according to season, region of isolation, and the age and sex of the patient.

RESULTS

The breakdown of the isolated pathogenic bacteria were as follows: Salmonella spp. 476 (13.5%), pathogenic Escherichia coli 777 (22.0%), Vibrio parahaemolyticus 26 (0.74%), Shigella spp. 13 (0.37%), Campylobacter spp. 215 (6.10%), Clostridium perfringens 508 (14.4%), Staphylococcus aureus 1,144 (32.4%), Bacillus cereus 356 (10.1%), Listeria monocytogenes 1 (0.03%), and Yersinia enterocolitica 10 (0.3%). The isolation rate trend showed the highest ratio in the summer season from June to September for most of the pathogenic bacteria except the Gram-positive bacteria. The isolation rate of most of the pathogenic bacteria by patient age showed highest ratio in the 0-19 year age range. For isolation rate by region, 56.2% were isolated from cities and 43.8% were isolated from provinces.

CONCLUSION

Hygiene education should be addressed for diarrheal disease-susceptible groups, such as those younger than 10 years, aged 10-19 years, and older than 70 years, and monitoring for the pathogens is still required. In addition, an efficient laboratory surveillance system for infection control should be continued.

Rotavirus incidence in hospitalised Hong Kong children: 1 July 1997 to 31 March 2011

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1.6% of hospitalized children below 5 years of age had a primary or any secondary discharge diagnosis of rotavirus.

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Incidence of discharge diagnosis of rotavirus was 1071 and 542/100,000 person-years below 2 and 5 years of age, respectively.

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A discharge diagnosis of rotavirus in children below 5 years of age likely under-reports true incidence by 1.59–2.02 times.

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Adjusted and unadjusted incidence of rotavirus and all-cause gastroenteritis trended up, not down, from 1997 to 2011.

Sentinel laboratory surveillance from one hospital and passive discharge diagnosis (Clinical Management System, CMS) data from all public Hospital Authority (HA) hospitals were used to estimate disease burden and incidence of rotavirus in hospitalised Hong Kong children over 14 rotavirus seasons (1 July 1997 to 31 March 2011). A primary diagnosis of a gastroenteritis-related disorder was noted in 9.8% of children aged below 5 years, and a primary or secondary diagnosis in 11.8%. Any CMS diagnosis of rotavirus (ICD 008.61) was initially used to derive incidence estimates of rotavirus by age group. Rotavirus was recorded as any primary or any secondary diagnosis in 1.6% of children below 5 years of age. The unadjusted incidence rates per 100,000 person-years based on any CMS diagnosis of rotavirus were: 249 (0 to <1m); 612 (1 to <2m); 1066 (2 to <6m); 1383 (6 to <11m); 959 (1 to <2y); 406 (2 to <3y); 233 (3 to <4y); 124 (4 to <5y). Overall the rotavirus incidence was 1071 in children below 2 years and 542 in children below 5 years of age, with the incidence rates trending up during the time period (p = 0.001). A similar but less marked upward trend (p = 0.046) was noted for the incidence of all-cause gastroenteritis. Laboratory results from a single surveillance hospital (1 July 2000 to 31 March 2011) were then linked to these CMS codes to derive adjustment factors for possible over- and under-diagnosis of rotavirus based on CMS codes alone. This analysis suggested that a CMS diagnosis of rotavirus alone likely under-reported true incidence by a factor of between 1.59 and 2.02 in children below 5 years of age. Despite the availability of rotavirus vaccines in the private sector since 2006, no reduction in the incidence of hospitalisation for either rotavirus or all-cause gastroenteritis was noted in Hong Kong children below 5 years of age over 14 rotavirus seasons (1997–2011).

Efficacy, safety and immunogenicity of a human rotavirus vaccine (RIX4414) in Hong Kong children up to three years of age: a randomized, controlled trial

BACKGROUND

A phase III, double-blind, randomized, controlled trial was conducted in Hong Kong to evaluate the efficacy, safety and immunogenicity of a human rotavirus vaccine, RIX4414 (Rotarix) against severe rotavirus gastroenteritis in children up to three years of age.

METHODS

Healthy infants aged 6-12 weeks were enrolled between 08-December-2003 and 31-August-2005 and received two oral doses of either RIX4414 vaccine (N=1513) or placebo (N=1512) given 2 months apart. Vaccine efficacy was assessed from two weeks post-Dose 2 until the children were two and three years of age. Anti-rotavirus IgA seroconversion rate was calculated pre-vaccination and 1-2 months post-Dose 2 using ELISA (cut-off=20 U/mL) for 100 infants. Safety was assessed until the children were two years of age; serious adverse events (SAEs) were recorded throughout the study period.

RESULTS

In children aged two and three years of life, vaccine efficacy against severe rotavirus gastroenteritis was 95.6% (95% CI: 73.1%-99.9%) and 96.1% (95% CI: 76.5%-99.9%), respectively. The seroconversion rate 1-2 months after the second dose of RIX4414 was 97.5% (95% CI: 86.8%-99.9%). At least one SAE was recorded in 439 and 477 infants who were administered RIX4414 and placebo, respectively (p-value=0.130). Six intussusception cases were reported (RIX4414=4; placebo=2) and none was assessed to be vaccine-related.

CONCLUSION

RIX4414 was efficacious, immunogenic and safe in the prevention of rotavirus gastroenteritis for at least two years post-vaccination in Hong Kong children.

Hospital discharge data: can it serve as the sole source of case ascertainment for population-based birth defects surveillance programs?

INTRODUCTION

Because of the relatively high expense of collecting primary data and limited resources, electronically available, population-based hospital discharge data have been increasingly used for disease surveillance by public health researchers. The objective of this study was to compare the New York State Congenital Malformations Registry (CMR) data, which relies on hospital reports, with the hospital discharge files to identify cases in the CMR that were missed in the hospital discharge data files. The ultimate goal was to evaluate whether hospital discharge data can serve as the sole source of case ascertainment for a population-based birth defects surveillance program.

METHODS

CMR cases that were born to the New York State residents for the years 2000 to 2005 were selected and matched to the hospital discharge files from the New York Statewide Planning and Research Cooperative System (SPARCS) for the same birth year period. Since the SPARCS database does not contain patient's name, extensive database matching and manual review by staff members were performed using identifying variables such as the hospital's permanent facility identifier, child's date of birth and medical record number, and mother's medical record number and residential address.

RESULTS

Out of 66 757 CMR cases selected for the study period, 62 118 cases (93.1%) were matched to SPARCS hospital discharge records with International Classification of Diseases, Ninth Revision (ICD-9) codes that were reportable to the CMR, 3 444 cases (5.2%) were matched to SPARCS records with ICD-9 codes that were not reportable to the CMR, and 1 195 cases (1.8%) were not matched. The percentage of cases with multiple congenital malformations was significantly higher (21.3%) for the matched cases that had reportable ICD-9 codes in SPARCS, compared with that for matched CMR cases that had no reportable ICD-9 codes in SPARCS (10.2%).

CONCLUSION

The study found that 93% of CMR infants selected for the study were matched to hospital discharge records with at least one ICD-9 code that was reportable to the CMR; 87 percent had reportable ICD codes in SPARCS that were exactly matched to those in the CMR, that is, all the birth defect codes in SPARCS were matched to those in the CMR. Thus, about 7 percent of CMR children with birth defects would have been missed if only hospital discharge files were used to ascertain the birth defect cases, indicating that there are limitations to using hospital discharge files as the sole source of case ascertainment for population-based birth defects surveillance programs.

Rotavirus surveillance to determine disease burden and epidemiology in Java, Indonesia, August 2001 through April 2004

This study estimates rotavirus disease burden in children under age 3 years presenting with acute gastroenteritis to hospitals in Purworejo district and Yogyakarta city from August 2001 to April 2004. Among a total of 8929 hospitalized children, 1397 (16%) presented with acute gastroenteritis and of the 1321 stool samples tested, 705 (53%) were positive for rotavirus. Rotavirus infections were most common among children aged 7-23 months and rotavirus was more common during the dry season (June through August). Logistic regression analysis showed no differences in socioeconomic indicators between the rotavirus positive and negative admissions. Rotavirus vaccination may prevent a large proportion of all hospitalizations of young children under 3 years of age presenting with acute gastroenteritis.

The epidemiology of hospitalization with diarrhea in rural Kenya: the utility of existing health facility data in developing countries

OBJECTIVES

In developing countries where prospective surveillance is resource-intensive, existing hospital data can define incidence, mortality, and risk factors that can help target interventions and track trends in disease burden.

METHODS

We reviewed hospitalizations from 2001 to 2003 at all inpatient facilities in Bondo District, Kenya.

RESULTS

Diarrhea was responsible for 11.2% (n=2158) of hospitalizations. The annual incidence was 550 and 216 per 100,000 persons aged <5 and > or =5 years, respectively. The incidence was highest in infants (1138 per 100,000 persons), decreased in older children, peaked again among 20-29-year-olds (341 per 100,000), and declined among those > or =65 years (157 per 100,000). Female adults had higher incidence than males (rate ratio=1.84, 95% CI 1.61-2.10). Incidence decreased with distance from the district referral hospital (4.5% per kilometer, p<0.0001) and from the nearest inpatient facility (6.6% per kilometer, p=0.012). Case-fatality was high (8.0%), and was higher among adults than young children. Co-diagnosis with malaria, pneumonia, HIV, and tuberculosis was common. Peak diarrhea incidence fell one to two months after heavy rains.

CONCLUSIONS

The trends revealed here provide useful data for public health priority setting and planning, including preventative interventions. The utility of such data justifies renewed efforts to establish and strengthen health management information systems in developing countries.

The Risk and Consequences of Clinical Miscoding Due to Inadequate Medical Documentation: A Case Study of the Impact on Health Services Funding

As coded clinical data are used in a variety of areas (e.g. health services funding, epidemiology, health sciences research), coding errors have the potential to produce far-reaching consequences. In this study the causes and consequences of miscoding were reviewed. In particular, the impact of miscoding due to inadequate medical documentation on hospital funding was examined. Appropriate reimbursement of hospital revenue in the casemix-based (output-based) funding system in the state of Victoria, Australia relies upon accurate, comprehensive, and timely clinical coding. In order to assess the reliability of these data in a Melbourne tertiary hospital, this study aimed to: (a) measure discrepancies in clinical code assignment; (b) identify resultant Diagnosis Related Group (DRG) changes; (c) identify revenue shifts associated with the DRG changes; (d) identify the underlying causes of coding error and DRG change; and (e) recommend strategies to address the aforementioned. An internal audit was conducted on 752 surgical inpatient discharges from the hospital within a six-month period. In a blind audit, each episode was re-coded. Comparisons were made between the original codes and the auditor-assigned codes, and coding errors were grouped and statistically analysed by categories. Changes in DRGs and weighted inlier-equivalent separations (WIES) were compared and analysed, and underlying factors were identified. Approximately 16% of the 752 cases audited reflected a DRG change, equating to a significant revenue increase of nearly AU$575,300. Fifty-six percent of DRG change cases were due to documentation issues. Incorrect selection or coding of the principal diagnosis accounted for a further 13% of the DRG changes, and missing additional diagnosis codes for 29%.The most significant of the factors underlying coding error and DRG change was poor quality of documentation. It was concluded that the auditing process plays a critical role in the identification of causes of coding inaccuracy and, thence, in the improvement of coding accuracy in routine disease and procedure classification and in securing proper financial reimbursement.

Enteric bacteria isolated from acute diarrheal patients in the Republic of Korea between the year 2004 and 2006

In an epidemiological survey of human enterobacterial infections in the Republic of Korea during three years from 2004 to 2006, we isolated 1,784 (6.2%, isolation rate of enteropathogens from stool samples) in 2004, 2,547 (9.5%) in 2005 and 3,506 bacteria (12.3%) from people who visited clinics. Among the isolated bacteria, pathogenic Escherichia coli, especially, EAEC was the most frequently identified pathogen in both urban and rural regions followed by Staphylococcus aureus, Salmonella species, Bacillus cereus, Vibrio parahaemolyticus, Campylobacter jejuni, Clostridium perfringens, and Shigella species. Distinct seasonality was found in V. parahaemolyticus species, while this pathogen showed no age-specific patterns. However, other bacteria, i.e., pathogenic E. coli, S. aureus, Salmonella spp., and B. cereus showed similar seasonality throughout the year, showing a slight increase in the infection rate during the summer months and high prevalence among children under 10 years of age and elder-age people. The antibiotic susceptibility patterns of pathogenic E. coli, Salmonella spp., and S. aureus showed high resistance to penicillins. However, both pathogenic E. coli and Salmonella spp. were susceptible to several cephems, imipenem, and amikacin. Moreover, S. aureus strains resistant to vancomycin were not found. In conclusion, these surveillances can play an important role for the control and prevention to the diseases originated by enteritis bacteria.

Estimates of Rotavirus Disease Burden in Hong Kong: Hospital‐Based Surveillance

BACKGROUND

We conducted prospective, hospital-based surveillance for rotavirus disease for a 2-year period at 4 of 12 public government (Hospital Authority [HA]) hospitals in Hong Kong. It has been estimated that HA hospitals provide 90% of inpatient care in Hong Kong.

METHODS

Information was collected for children <5 years old who had a primary or secondary diagnosis of diarrhea or for whom a stool sample was tested for the presence of rotavirus (by enzyme immunoassay) or bacteria (by culture). Surveillance data were compared with routine discharge information from the HA's computerized Clinical Management System (CMS).

RESULTS

During a 2-year period (1 April 2001 through 31 March 2003), 7391 children were admitted to the hospital with diarrhea or developed diarrhea during their hospital stay. Of these children, 5881 (80%) had a stool sample tested for the presence of rotavirus, and 30% were positive for rotavirus (representing 24% of all diarrhea-associated admissions). CMS data underreported the total percentage of diarrhea-associated admissions (15% vs. 20%) and the percentage of diarrhea-associated admissions that were the result of rotavirus infection (13% vs. 24%). Estimated rates of hospitalization for rotavirus infection (8.8 admissions/1000 children <5 years old and 18.4 admissions/1000 children <1 year old) were 4-fold higher than our previous estimates, which were determined on the basis of CMS data alone. We estimate that the cumulative risk of hospitalization with rotavirus diarrhea by age 5 years is 1 in 24. Combined active and passive (CMS) surveillance data indicate that 4.6% of all general pediatric admissions to HA hospitals in Hong Kong were associated with rotavirus infection.

CONCLUSION

Our study combined passive surveillance data from all Hong Kong HA hospitals with active surveillance data from 4 sentinel hospitals. The estimates of rotavirus disease burden obtained will help emphasize the effect of this important disease and create awareness of the potential for rotavirus vaccines. The surveillance model developed could also be a powerful tool for monitoring the effect of a vaccine.

Outbreaks of viral gastroenteritis: whatʼs new in 2004?

PURPOSE OF REVIEW

Descriptions of outbreaks of viral gastroenteritis have become a prominent feature in scientific journals and other media such as the electronic reporting service 'promed'. A review of outbreak reports was done to further our understanding of the burden of disease, common and rare modes of transmission, complications, and possibilities for control and prevention.

RECENT FINDINGS

Viral gastroenteritis outbreaks occur worldwide. In 2004, besides outbreak reports and surveys, there was considerable attention paid to food and waterborne outbreaks and the difficulties in proving these modes of transmission. Costs of viral gastroenteritis outbreaks are high. Complications and unusual manifestations of viral gastroenteritis, such as convulsions, transplant rejection, and chronic infection, may have been underreported.

SUMMARY

Viral gastroenteritis is a very common illness in health care settings that can cause significant disruption. Clinicians working in these settings should be familiar with the epidemiology and the possible modes of transmission of enteric viruses to be able to translate them into strategies for prevention or intervention. Research is needed to support these strategies.