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Pharyngitis Complications in North America in the 21st CenturyDo current guidelines lead to overdiagnosisand overtreatment

Dr. Ian Johnston MBChB, BSc (Hons)

Dr. James Dickinson, Dr. Carmen Gittens1st September 2015

CUMMING SCHOOL OF MEDICINEDepartment of Family Medicine

Conflicts of Interest

None to disclose

Preventing Overdiagnosis – September 2015

Background

Acute Rheumatic Fever (ARF) — Immunologic sequelae— Group A streptococcus (GAS) infection— Can lead to Rheumatic Heart Disease (RHD).

ARF links to GAS pharyngitis established 1950s.— Warren Air Force Base (Southern Wyoming).

Studies supported antibiotic prescription to reduce incidence of ARF.

— Conclusions largely supported by recent Cochrane reviews. Two thirds reduction in chance of ARF with primary antibiotics.

o Where this complication is common.


Background


Cochrane database Syst Rev. 2013;11(11). doi:10.1002/14651858.CD000023.pub4.

Background

ARF already declining before penicillin.— Improvements in hygiene and overcrowding.

ARF and RHD still a significant cause of morbidity.— Developing world— Aboriginal communities in Australia/New Zealand.


Background

U.S. CDC made ARF not notifiable 1994.— Incidence <1 per million.— Isolated reports since. e.g. Utah late 90s.

Canadian Pediatric Surveillance Program (2004-2007)— 2.9 per million (<18 population)

Other western countries incidence very low. Guidelines worldwide:

— Swab & treat for GAS to prevent non-suppurative (ARF) and suppurative complications.


Objectives

Current rate in Canada? Relationship to aboriginality and crowding?


Methods

Retrospective study of routinely collected data. Canadian Institute for Health Information (CIHI) admission data

(ICD10-CA codes) from 2004/5-2010/11 with a “most responsible” or secondary diagnosis of ARF including:

— I00 - Rheumatic fever without mention of heart involvement— I01 - Rheumatic fever with heart involvement— I02 - Rheumatic chorea

Includes all discharges from acute inpatient care across Canada with an age <18 (excludes Quebec).

Canadian census data— Aboriginal population by health region.— Crowded dwellings >1 person/room.


Results


275 cases identified - 7 year study period— 5.58/million under 18 population (7.04 million).

6% of under 18s live in predominantly aboriginal communities.

Results


0.00

10.00

20.00

30.00

40.00

50.00

60.00

70.00

80.00

90.00

100.00

0.00 5.00 10.00 15.00 20.00 25.00

Perc

etan

ge A

borig

nal

Proportion Crowding

Results


0.00

20.00

40.00

60.00

80.00

100.00

120.00

140.00

0.00 10.00 20.00 30.00 40.00 50.00 60.00 70.00 80.00 90.00 100.00

Hosp

italis

atio

n ra

te p

er m

illio

n <1

8

Percentage Aboriginal Population

Keewatin Yatthu, SK

Mamawetan Churchill River, SK

Burntwood, MB

Results


0.00

20.00

40.00

60.00

80.00

100.00

120.00

140.00

0.00 5.00 10.00 15.00 20.00 25.00

Hosp

italis

atio

n ra

te p

er m

illio

n <1

8

Proportion Crowding

Burntwood, MB

Keewatin Yatthu, SK

Mamawetan Churchill River, SK

BurntwoodRate: 138.81

Mamawetan Churchill River Rate: 70.48

Keewatin YattheRate:103.00

Quebec Regional data not available

0.0-4.9

10.0-19.9

20.0-29.930.0-59.9

ARF Hospitalization Rate (per year, per 1,000,000 persons <18y)

60.0+

5.0-9.9

Quebec (Regional data not available)

Results

Results


Likely overestimation:— Data is individual hospitalizations.— Each child admitted locally, then transferred for specialist

assessment/echo etc. Each case appears in data twice.

— Any recurrence in the 7 year period will be admitted again (also twice).

Discussion


Common Belief

Need to have a sore throat to get ARF.

Every GAS sore throat may cause ARF.

Every case of ARF will get RHD.

Oral antibiotics needed to prevent RHD

Evidence

80% of cases of ARF no recollection of antecedent throat infection.

Repeated infections to trigger first episode of ARF.Not all Group A strep strains rheumatogenic.

40% of cases of RHD no recognized history of ARF.Repeated ARF necessary to progress to RHD.

Secondary prophylaxis with IM penicillin following ARF most cost effective way to prevent RHD.

Discussion


Lancet. 2012;379(9819):953-964. doi:10.1016/S0140-6736(11)61171-9.

Discussion

Antibiotics/otitis media.— 1 in 14 children treated with antibiotics = adverse event

(vomiting/diarrhea/rash)Cochrane Database Syst Rev. 2013;(1). doi:10.1002/14651858.CD000219.pub2. International collaborative study of severe anaphylaxis.

— Oral antibiotics = Low risk (5-15/100 000 exposed patients).Pharmacoepidemiol Drug Saf. 2003;12(3):195-202. doi:10.1002/pds.822.

Scottish study 1985- NNT of >100 000J R Coll Gen Pract. 1985;35(274):223-224. >7000 additional cases vomiting/diarrhea/rash 5-15 Anaphylactic/anaphylactoid reactions.


Discussion

7.3 Million pediatric sore throats annually (US data).— Antibiotics 53%. Not recommended ones 27% (increased resistance).

J Am Med Assoc. 2005;294(18):2315-2322. doi:10.1001/jama.294.18.2315.

~95% pharyngitis viral.— 20% of children asymptomatic chronic carriers of GAS.

Can Fam Physician. 2011;57(7):791–4. Clin Infect Dis. 2012;55(10):86–102. doi: 10.1093/cid/cis629

Clinical prediction rules don’t help decide who to swab.Can Med Assoc J. 2014;187(1):23-32. doi:DOI:10.1503 /cmaj.140772.


Further Work

CIHI currently re-running the numbers up to 2014 Including suppurative complications of GAS

— J36 – Peritonsillar abscess— J39.0 – Retropharyngeal and parapharyngeal abscess

Watch this space……


Conclusion

ARF rare in western countries. Other complications rare/easily managed.

— Further supportive data anticipated Antibiotics unacceptable risk of harm. Consider antibiotics in high risk.

— ~6% Canadian kids. Secondary antibiotics in remainder.

— ~94% Canadian kids. Guidelines need to change to reflect this.


[email protected] Overdiagnosis – September 2015

QuestionsTry not to see a wolf when it’s not there!

Photograph of Peyto Lake, Banff national park AB - Courtesy Breanna Uzelman

Acknowledgements:• Dr. Gittens and Dr.

Dickinson for the initial work, help and support with project.

• Grace Perez for statistical support.

• Analysts at CIHI for data support.

mailto:[email protected]

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