Has the Quality and Outcomes Framework resulted in more timely diagnosis of COPD in

primary care?

LC Hunter, CM Fischbacher, N Hewitt, D McAllister, S Wild, RM Hardie

Lothian COPD data linkage project

• COPD cohort study to identify risk factors in primary care for emergency hospital admission

• Data linkage - primary care data linked to secondary care admissions data and death data.

• Eligible patients = diagnostic Read code for COPD in primary care record recorded between 1st April 2000 and 31st March 2008.

• Date of COPD diagnostic code proxy for date of diagnosis in primary care.– Use as time zero in analysis of time to first admission.

Date of COPD diagnostic coding

Patient becomes symptomatic

Patient coded as COPD =date of diagnosis

Intervention pre-diagnosis

Cohort=7002 patients from 72 practices

Read codes for COPD 1st April 2000- 31st March 2008.

Patient presents to GP with symptoms of COPD

?- acute exacerbation (treated in primary care) - Respiratory drug

Intervention pre-diagnosis of COPD

Patient becomes symptomatic

Patient presents to GP with symptoms of COPD (n=7002)

Patient coded as COPD =date of diagnosis

Intervention pre-diagnosis median time 3 yrs

(IQR: 0.1-6.2)

n=3504 (50%)

n=3498 (50%)

Intervention pre-diagnosis and gender

0

500

1000

1500

2000

2500

Male Female

No intervention pre-diagnosis

Intervention pre-diagnosis

52% 48%

43%57%

p<0.001 (Chi square)

Intervention pre-diagnosis of COPD - gender

Patient becomes symptomatic

Patient presents to GP with symptoms of COPD (n=7002)

Patient coded as COPD =date of diagnosis

Intervention pre-diagnosis

Females: median time 3.6yrs (IQR:1-6.6)

Males: median time 2.7yrs (IQR: 0.9-5.6)p<0.001 (Mann Whitney)

Intervention pre-diagnosis by SIMD quintile

0

200

400

600

800

1000

1200

1400

Q1 Q2 Q3 Q4 Q5

No interventionpre-diagnosis

Intervention pre-diagnosis

46%

54%

48%

52%

48%52%

51%

49%

50%50%

p<0.05 (Chi square)

Intervention pre-diagnosis of COPD - deprivation

Patient becomes symptomatic

Patient presents to GP with symptoms of COPD (n=7002)

Patient coded as COPD =date of diagnosis

Intervention pre-diagnosis

p<0.05 (Mann Whitney)

Q1 (most deprived): median time 3.1yrs (IQR:1.1-6.2)

Q5 (least deprived): median time 2.5yrs (IQR: 0.7-6.0)

Summary

• Interventions pre-diagnosis– Higher proportion of females – Higher proportion of patients in more deprived

quintiles– Longer time from intervention to diagnosis in these

groups

• Differences in gender and deprivation?– Females and patients in more deprived areas present

earlier with milder COPD symptoms?– And/or delay in recognising/confirming COPD in these

patients?

QOF and date of diagnostic coding?

Cohort start 01/04/2000

Cohort end 31/03/2008

01/04/2004 = start of QOF

Intervention

Diagnostic code

?Intervention

Diagnostic code

?

Pre-start of QOF Post-start of QOF

QOF and date of diagnostic coding?

01/04/2004 = start of QOF

Interventions pre-diagnosis n=1578 (47%)*

Interventions pre-diagnosis n=1920 (53%)*

Cohort start 01/04/2000

Pre-start of QOF Post-start of QOF

Cohort end 31/03/2008

Intervention Diagnostic

codeIntervention

Diagnostic code

*p<0.001 Chi square

**p<0.0001 Mann Whitney

Median time 2.7yrs (IQR 1-5.3)** Median time 3.4yrs (IQR 0.9-7.2)**

Patients with interventions pre-diagnosis before and after QOF by gender

0

200

400

600

800

1000

1200

Males Females

Pre-QOF

Post-QOF

* **

* p<0.05 (Chi square) **p<0.0001 (Chi square) ***p<0.0001 (Mann Whitney)

Median time from intervention to diagnosis*** Pre-QOF= 2.8yrs (1-5.4) Post-QOF= 4.3yrs (1.1-7.8)

47% 53% 44% 56%

Patients with interventions pre-diagnosis before and after QOF by deprivation quintile

0

100

200

300

400

500

600

700

Q1 Q2 Q3 Q4 Q5

Pre-QOF

Post-QOF

46%

54%

46%

54%

45%49%

42%

58%

55%

55%45%

Has QOF resulted in more timely diagnosis of COPD?

• After start of QOF:– Higher proportion of male and female patients across all quintiles have

interventions pre-diagnosis– Longer time from intervention to diagnosis for females.

• Reasons?– Improved quality of coding post-QOF?

• Patient not coded until fulfils disease register criteria.

– Retrospective case finding with contemporary date of coding?

• Differences in gender?– More retrospective case finding in females?– Presenting earlier with disease and taking longer to fulfil QOF disease

register criteria

Limitations and conclusions

Limitations• Data not adjusted for severity at presentation/diagnosis.• Only patients diagnosed in first four years of QOF

analysed.

Conclusions• Date of diagnostic coding frequently does not reflect date

a patient first treated for COPD in primary care.• Varies by sex, deprivation and time (in relation to QOF)• Researchers need to be aware of these potential issues

when using date of diagnostic coding in analysis.

Acknowledgements

• ISD data linkage team• Lothian GP practices that participated in Lothian

COPD cohort study• Dr John Steyn NHS Lothian eHealth clinical

adviser