Estimating the likely true changes in rheumatic fever incidence using two data sources

Acute rheumatic fever and rheumatic heart disease in children and adolescents in Victoria, Australia

AIM

To describe the epidemiology and clinical profile of children and adolescents with acute rheumatic fever (ARF) and rheumatic heart disease (RHD) in Victoria, Australia.

METHODS

A retrospective audit was undertaken of children and adolescents with ARF and RHD attending the Royal Children's and Monash Children's Hospitals in Victoria, Australia between 2010 and 2019. Potential cases were identified by searching multiple sources for relevant ICD-10-AM codes and keywords, then reviewed manually. For confirmed cases, we collected data on patient demographics, clinical features, comorbidities and management.

RESULTS

Of 179 participants included, there were 108 Victorian residents and 71 non-Victorian residents. 126 had at least one episode of ARF during the study period and 128 were diagnosed with RHD. In the Victorian resident group, the overall incidence of ARF was 0.8 per 100 000 5-14 year olds. This incidence was higher in Victorian Aboriginal and/or Torres Strait Islander (3.8 per 100 000) and Pacific Islander (32.1 per 100 000) sub-populations. Of 83 Victorian residents who had an ARF episode, 11 (13%) had a recurrence. Most Victorian residents with RHD had mixed aortic and mitral valve pathology (69.4%) and moderate to severe disease (61.9%). Most non-Victorian residents were Aboriginal and/or Torres Strait Islander people (80.3%) and were commonly transferred for tertiary or surgical management of RHD (83.1%).

CONCLUSIONS

ARF and RHD continue to affect the health of significant numbers of children and adolescents living in Victoria, including severe and recurrent disease. Specialised services and a register-based control program may help to prevent complications and premature death.

C10Pred: A First Machine Learning Based Tool to Predict C10 Family Cysteine Peptidases Using Sequence-Derived Features

Streptococcus pyogenes, or group A Streptococcus (GAS), a gram-positive bacterium, is implicated in a wide range of clinical manifestations and life-threatening diseases. One of the key virulence factors of GAS is streptopain, a C10 family cysteine peptidase. Since its discovery, various homologs of streptopain have been reported from other bacterial species. With the increased affordability of sequencing, a significant increase in the number of potential C10 family-like sequences in the public databases is anticipated, posing a challenge in classifying such sequences. Sequence-similarity-based tools are the methods of choice to identify such streptopain-like sequences. However, these methods depend on some level of sequence similarity between the existing C10 family and the target sequences. Therefore, in this work, we propose a novel predictor, C10Pred, for the prediction of C10 peptidases using sequence-derived optimal features. C10Pred is a support vector machine (SVM) based model which is efficient in predicting C10 enzymes with an overall accuracy of 92.7% and Matthews’ correlation coefficient (MCC) value of 0.855 when tested on an independent dataset. We anticipate that C10Pred will serve as a handy tool to classify novel streptopain-like proteins belonging to the C10 family and offer essential information.

Preceding group A streptococcus skin and throat infections are individually associated with acute rheumatic fever: evidence from New Zealand

Introduction

Acute rheumatic fever (ARF) is usually considered a consequence of group A streptococcus (GAS) pharyngitis, with GAS skin infections not considered a major trigger. The aim was to quantify the risk of ARF following a GAS-positive skin or throat swab.

Methods

This retrospective analysis used pre-existing administrative data. Throat and skin swab data (1 866 981 swabs) from the Auckland region, New Zealand and antibiotic dispensing data were used (2010–2017). Incident ARF cases were identified using hospitalisation data (2010–2018). The risk ratio (RR) of ARF following swab collection was estimated across selected features and timeframes. Antibiotic dispensing data were linked to investigate whether this altered ARF risk following GAS detection.

Results

ARF risk increased following GAS detection in a throat or skin swab. Māori and Pacific Peoples had the highest ARF risk 8–90 days following a GAS-positive throat or skin swab, compared with a GAS-negative swab. During this period, the RR for Māori and Pacific Peoples following a GAS-positive throat swab was 4.8 (95% CI 3.6 to 6.4) and following a GAS-positive skin swab, the RR was 5.1 (95% CI 1.8 to 15.0). Antibiotic dispensing was not associated with a reduction in ARF risk following GAS detection in a throat swab (antibiotics not dispensed (RR: 4.1, 95% CI 2.7 to 6.2), antibiotics dispensed (RR: 4.3, 95% CI 2.5 to 7.4) or in a skin swab (antibiotics not dispensed (RR: 3.5, 95% CI 0.9 to 13.9), antibiotics dispensed (RR: 2.0, 95% CI 0.3 to 12.1).

Conclusions

A GAS-positive throat or skin swab is strongly associated with subsequent ARF, particularly for Māori and Pacific Peoples. This study provides the first population-level evidence that GAS skin infection can trigger ARF.

Ethnically Disparate Disease Progression and Outcomes among Acute Rheumatic Fever Patients in New Zealand, 1989-2015

We investigated outcomes for patients born after 1983 and hospitalized with initial acute rheumatic fever (ARF) in New Zealand during 1989-2012. We linked ARF progression outcome data (recurrent hospitalization for ARF, hospitalization for rheumatic heart disease [RHD], and death from circulatory causes) for 1989-2015. Retrospective analysis identified initial RHD patients <40 years of age who were hospitalized during 2010-2015 and previously hospitalized for ARF. Most (86.4%) of the 2,182 initial ARF patients did not experience disease progression by the end of 2015. Progression probability after 26.8 years of theoretical follow-up was 24.0%; probability of death, 1.0%. Progression was more rapid and ≈2 times more likely for indigenous Māori or Pacific Islander patients. Of 435 initial RHD patients, 82.2% had not been previously hospitalized for ARF. This young cohort demonstrated low mortality rates but considerable illness, especially among underserved populations. A national patient register could help monitor, prevent, and reduce ARF progression.

The economic and health burdens of diseases caused by group A Streptococcus in New Zealand

OBJECTIVES

In preparation for the future arrival of a group A Streptococcus (GAS) vaccine, this study estimated the economic and health burdens of GAS diseases in New Zealand (NZ).

METHODS

The annual incidence of GAS diseases was based on extrapolation of the average number of primary healthcare episodes managed each year in general practices (2014-2016) and on the average number of hospitalizations occurring each year (2005-2014). Disease incidence was multiplied by the average cost of diagnosing and managing an episode of disease at each level of care to estimate the annual economic burden.

RESULTS

GAS affected 1.5% of the population each year, resulting in an economic burden of 29.2 million NZ dollars (2015 prices) and inflicting a health burden of 2373 disability-adjusted life years (DALYs). Children <5 years of age were the most likely age group to present for GAS-related healthcare. Presentations for superficial throat and skin infections (predominantly pharyngitis and impetigo) were more common than other GAS diseases. Cellulitis contributed the most to the total economic and health burdens. Invasive and immune-mediated diseases disproportionately contributed to the total economic and health burdens relative to their frequency of occurrence.

CONCLUSION

Preventing GAS diseases would have substantial economic and health benefits in NZ and globally.

Incidence of acute rheumatic fever and rheumatic heart disease in Melbourne, Australia from 1937 to 2013

AIM

Acute rheumatic fever (ARF) most commonly presents in children aged 5-14 years old. Lifelong rheumatic heart disease (RHD) can result. This study investigated time trends in ARF and RHD using inpatient data from the Royal Children's Hospital, Melbourne (RCH).

METHODS

A retrospective cohort study covering the period 1937-2013 was conducted using records from RCH, a quaternary paediatric hospital in Melbourne, Victoria, Australia. Patient data were identified using RCH classification of diseases coding for ARF or RHD for years <1952. For the period 1952-1987, this system was used in addition to identifying International Classification of Disease (ICD) discharge codes that corresponded to ARF or RHD. From 1988-2013, only ICD codes were used to identify patient data. Descriptive epidemiological analyses were performed, including incidence rate calculations using historical census population denominator data. Analyses focussed on children in the peak age group.

RESULTS

Among children aged five to 14 years, a total of 4337 RCH admissions with ARF/RHD occurred for 3015 patients. A sharp decline in first ARF/RHD hospitalisations at RCH occurred from 1959, following a peak mean annual incidence rate during 1944-1947 of 40.1/100 000 children (95% confidence interval (CI): 36.6-43.9; P < 0.05). Over 1996-2013, the mean annual incidence rate was 1.6/100 000 (95% CI: 1.3-1.8) and reached 2.3/100 000 (95% CI: 1.3-3.7) in 2005.

CONCLUSION

The burden of ARF and RHD treated at RCH declined following the 1940s, mirroring changes seen in North America and Europe. Despite this, inpatient treatment for these conditions continued to be provided right up until the end of the study period.