Is Some Physician Advice on Smoking Cessation Better Than No Advice?

An Instrumental Variable Analysis of the 2001 National Health Interview Survey

Yuhua Bao, Ph.D.

Naihua Duan, Ph.D.

Sarah Fox, Ed.D.

UCLA

Academy Health Annual Research Meeting

June 6, 2004

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One-third smoking patients do not receive any medical advice to quit smoking

Nearly 1/4 of American adults remain smokers in 2001

Of all the adult smokers, 65% had some contact with health care providers annually. However,

About 1/3 of these smoking patients were not advised to quit by their providers.

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Providers lack confidence in the effectiveness of their advice

Various barriers exist in providers’ intervention for smoking cessation

One barrier is providers’ lack of confidence Disbelief that their advice would deter patients Belief that successful intervention requires excessive time

commitment

Few have studied the effectiveness of provider advice performed in routine practice.

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Why is evidence from RCTs not enough?

Advice compared to “routine care”

Well-defined intervention modalities, certain length of discussion by certain type of providers

Advice only

Choose between advice and no advice

Develop strategies suitable for their own practice

Provide advice and additional help as needed

RCTs tell the effectiveness of … Practitioners need to …

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Data: NHIS 2001 Sample Adult File

n % of reference population

Entire Sample 5,512 100 Current Smokers 4,975 90 Patients who reported quitting in the past 12 months

537

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Patients who received some advice to quit smoking

3,596

66

Adults

1) Who were either current smokers or quit smoking during the last 12 months, and

2) Who had contact with their regular health providers in the past 12 months

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Patients advised vs. not advised

Patient Characteristics Advised Not Advised

Quit smoking in the last 12 months***

0.07

0.16

Years of regular smoking*

26.2 23.1

# of cigarettes smoked per day** (current smokers only)

16.4 13.1

Serious cardiovascular conditions***

0.12 0.07

Other heart conditions 0.35 0.26 Lung-breathing related conditions** 0.26 0.18 Cancer*** 0.10 0.07 n

3,596 1,916

Source: NHIS 2001

* p<0.1; **p<0.05; ***p<0.01

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Use provider advice for diet and physical activity as IVs for smoking cessation

advice

Quit Quit smoking in the last 12 months (0,1) Advice Received advice to quit smoking in the last 12 months (0, 1)

XA Patient age group, presence of smoking-related conditions

XQ Variables in XA, age started smoking, gender, education,

living with spouse, working now, social support index

Z (IVs) 1) Provider advised on diet/nutrition (0,1) 2) Provider advised on physical activity (0,1)

Ai

AAii

Ai XZAdvice ''*

Qi

QQii

Qi XAdviceQuit '**

.1

1,

0

0~

BVNQ

A

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Results: Effect of some advice on one-year smoking cessation

Entire Sample

Patients with no smoking-related

conditions

No advice

Some Advice

No advice

Some Advice

IV estimation (bi-probit)

6.9% 14.8% 7.3% 13.8%

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Results: Effect of some advice on one-year smoking cessation

Entire Sample

Patients with no smoking-related

conditions

No advice

Some Advice

No advice

Some Advice

IV estimation (bi-probit)

6.9% 14.8% 7.3% 13.8%

Single Probit 15.4% 7.0% 14.0% 6.8%

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Conclusions

Smoking cessation advice as performed in routine care doubles the probability of self-reported abstinence within one year.

Community practitioners should be Informed of the effectiveness of the way they currently

advise, and encouraged to provide consistent and universal advice