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Chronic Obstructive Pulmonary Disease H001

Document
Last amended 
3 April 2016
Current RMA Instruments:
Reasonable Hypothesis SOP
37 of 2014 as amended by 128 of 2015
Balance of Probabilities SOP
38 of 2014 as amended by 129 of 2015
Changes from Previous Instruments:

SOP Bulletin 186

ICD Coding:
  • ICD-9-CM Codes: 491,492.0-492.8
  • ICD-10-AM Codes: J41,  J42,  J43,  J44
Brief description

This SOP covers: chronic bronchitis (with or without obstruction); emphysema; and chronic airflow limitation where it is due to respiratory irritants (particularly smoking).  It does not cover chronic airflow limitation / obstructive pulmonary disease due to other causes, particularly asthma.  The terminology in this field can be given different meanings in different settings and can be confusing.  There are a range of other lung diseases that can present in a similar way, that are not covered by this SOP.  Symptoms and clincial findings require careful evaluation and diagnosis can be difficult. 

Confirming the diagnosis

A diagnosis of chronic bronchitis requires evidence of cough with sputum production as specified in the SOP definition.

A diagnosis of emphysema will generally be made based on spirometry showing chronic airflow limitation (see below), or a high resolution CT lung scan showing the disease, or other specific lung function studies, reported by a respiratory physician.

Accurate diagnosis of chronic airflow limitation requires maximal effort post bronchodilator spirometry, with repeatable results obtained on calibrated equipment.  This generally means respiratory function testing undertaken at a respiratory laboratory. 

Note: Chronic airflow limitation is not separately diagnosed if it is an integral manifestation of another diagnosed respiratory disease.

The relevant medical specialist is a respiratory physician.  A report froma respiratory physician should be obtained where possible to establish the correct diagnosis. 

Additional diagnoses covered by the SOP
  • Chronic airflow limitation – not due to another disease.
  • Chronic bronchitis
  • Chronic obstructive bronchitis
  • Chronic obstructive airways disease– not due to another disease
  • Chronic obstructive lung disease– not due to another disease
  • Chronic simple bronchitis
  • Emphysema
Conditions excluded from the SOP
  • Acute or recurrent bronchitis#, ICD code 466.0
  • Asthma*
  • Bronchiectasis*
  • Bronchiolitis obliterans#, ICD code 519.8
  • Chronic airflow limitation due to asthma*
  • Chronic airflow limitation due to asbestosis*
  • Chronic airflow limitation due to bronchiectasis*
  • Chronic airflow limitation due to extrinsic allergic alveolitis*
  • Chronic airflow limitation in fibrosing interstitial lung disease*
  • Emphysema that is localised, focal or unilateral#, ICD code 519.8
  • Hyperlucent lung syndrome#, ICD code 492.9
  • isolated emphysematous bleb#, ICD code 519.8
  • MacLeod’s syndrome#, ICD code 492.9
  • Surgical emphysema#, ICD code 998.8
  • Swyer-James syndrome#, ICD code 492.9
  • Traumatic emphysema#, ICD code 958.7

* another SOP applies  - the SOP has the same name unless otherwise specified

# non-SOP condition

Clinical onset

The clinical onset depends on the type of disease. 

  • For chronic bronchitis, once the diagnosis is confirmed, the clinical onset will date from the start of the first period of time when the necessary cough (productive of sputum for 3 months, not due to another condition) was present.
  • For emphysema, clinical onset can be determined based on the first demonstration of the relevant pathological changes on (high resolution) CT scan of the lungs.  The onset can also be determined on clinical grounds based on shortness of breath and the first demonstration of a non-reversible obstructive pattern on spirometry (FEV1 < 80% or normal and FEV1/FVC < 70%), or the first evidence of significant gas trapping on measurement of diffusing capacity (DLCO), provided these findings have been interpreted by a specialist physician as being attributable to emphysema (and not some other disease).
  • For chronic airflow limitation the clinical onset will be when (reliable) spirometry results first demonstrated the necessary, non-reversible pattern (FEV1 < 80% or normal and FEV1/FVC < 70%), and the results have been interpreted by a specialist physician as being attributable to emphysema (and not some other disease).
Clinical worsening

The normal course of chronic obstructive pulmonary disease is generally for it to slowly worsen over time and for episodic exacerbations to occur.  Cessation of smoking can lead to an improvement in symptoms, particularly for chronic bronchitis.  Worsening can be demonstrated by an increase in symptoms, a decline in exercise tolerance, or a deterioration in test results (e.g. spirometry).  Whether there is deterioration over and above the normal course of the disease will be a matter for medical judgement.  Treatment may improve symptoms and can prevent or reduce exacerbations and prolong survival, but will generally not significantly alter the underlying pathology of the disease.