From the Bench to Public Health

Background

Early detection of colorectal cancer (CRC) using fecal occult blood test (FOBT) reduces mortality, yet screening adherence remains low.

Purpose

Enhancing FOBT adherence in a field experiment, using Implementation Intentions (II) technique.

Design

Participants were randomly assigned to a standard care group or to II experimental group.

Setting/participants

A test kit was mailed to 29,833 HMO-insured members in two waves in 2011. Inclusion criteria: eligible persons aged 50–74 who underwent the test the year before. A sample of 2200 participants was interviewed over the telephone for possible cognitive and background moderators.

Intervention

Leaflet attached to the test kit containing an “if–then” condition and planning instructions of when, where, and how.

Main outcome measure

Test performance at 2 and 6 months following mailing of the test kit, retrieved from HMO’s computerized database (2011–2012).

Results

Adherence in the experimental group ranged 1.2%–6.6% higher than in the control group. Within 6 months of kits’ mailing, test uptake for the two waves was 71.4% and 67.9% for experiment and control, respectively (χ²=40.58, p=0.0001). The difference remained significant after controlling for age, gender, marital status, and wave (OR=1.17, 95% CI=1.11, 1.23, p<0.0001). Test performance was related to cognitive and background variables. No interaction was found among cognitive or background variables and the intervention.

Conclusions

II technique is useful in increasing adherence to CRC screening, even in a mailed form rather than a face-to-face experimental situation. Mailed II is an inexpensive and effective method, applicable for public health.

Introduction

Colorectal cancer, a fatal, frequent disease for which there is a cure if detected early, is diagnosed in Israel mainly in its later stages. There is a professional consensus that CRC screening for average-risk adults aged 50–74 is beneficial, as reflected by recommendations of policy-making health organizations in many countries.1, 2, 3, 4, 5 This consensus is based on evidence from several randomized trials of CRC mortality reduction in screened versus nonscreened populations, using fecal occult blood test (FOBT), a noninvasive, simple, and inexpensive method acceptable to the public.6, 7, 8 The success of CRC screening in reducing mortality depends on individuals in the target population agreeing to test. In Israel, the Ministry of Health policy recommendation⁹ is to undergo a routine, annual FOBT for average-risk asymptomatic individuals aged 50–74 years. The test is free of charge to eligible individuals by all HMOs, yet adherence to FOBT has been rising slowly: The average adherence rate to FOBT in Clalit Health Services (CHS) rose from 0.6% in 1995 to its current 40%, with various attempts over the years to enhance adherence of subgroups in the target population.10, 11

A need to design evidence-based, theoretically derived interventions to increase the level of FOBT screening was identified. Traditionally, most interventions attempt to increase knowledge or motivation (e.g., using the health belief model, theory of planned behavior); many have been successful.12, 13 A relatively new method—Implementation Intentions (II)—attempts to influence the volitional process, that is, to assist individuals who have adopted behavioral goals to realize their intentions, thus bridging the intention–behavior gap.¹⁴

Whereas intentions are general statements about the intent to pursue a certain goal (“I intend to achieve X”), implementation intentions are specific statements referring to the intention to perform a certain goal-directed behavior in applicable situations (i.e., “If situation Y is encountered, then I will initiate goal-directed behavior X”). Moreover, implementation intentions formation specifies the when, where, and how of reaching a goal. This involves clarifying, in advance, what behavior(s) need to be performed in order to reach the goal (in the “then” part of the plan) and specifying the relevant situational context (in the plan’s “if” part). For example, to achieve the goal of reliably performing FOBT, one could specify: “If I opened the kit” in the “if” part of the plan, “then I will place it on the bathroom windowsill” in the “then” part. Evidence indicates that II technique is effective in promoting intention attainment and goal realization.15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29 The method has been widely applied in the health behaviors domain in recent years, targeting diverse behaviors such as dietary behavior (targeting fat, fruits, and vegetables); physical activity; smoking cessation; and screening behaviors.17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29

“If–then” and “when–where–how” plans facilitate goal achievement through two mechanisms. First, specifying a future situation is assumed to activate the mental representation of the situation, making it more accessible, and in turn more detectable when it arises, even if a person is otherwise absorbed.³⁰ Second, mentally linking a situation with a goal-directed behavior is assumed to lead to the automatic initiation of the specified behavior, as in the case of habit; once the situation has been encountered, the intended behavior is automatically initiated. The automation transfers goal-directed behavior from effortful, conscious control into reacting to situational cues.¹⁶

Nearly all interventions in the health domain that followed the II experimental procedure induced participants to formulate their own plans and specify their own “if–then” contingencies.18, 20, 22, 24, 26, 29, 31, 32, 33, 34, 35, 36 Indeed, studies that closely examined the process of planning or forming II propose that “forming implementation intentions of maximal specificity is crucial for behavior change,”28, 31 and that a short planning session (e.g., via the Internet) is ineffective in changing behavior.³⁷ Nevertheless, the application of the II intervention to a population in the present study entailed a shift in the procedure. This included two components: first, an instruction leaflet was sent to participants by mail, a delivery mode that does not ensure that they read and applied the intervention; second, the leaflet contained suggestions for overcoming common problems that individuals face in attempting to perform the FOBT screening test, and an encouragement to adapt the suggestions to one’s circumstances. The present study is thus innovative in two ways: first, applying the II intervention in a “lean” mode (attempted only once previously³⁸); second, testing it on a population-level sample, larger by order of magnitude than in previous studies.25, 37, 38, 39

The purpose of the present study was to increase testing rates in CHS’s target population for CRC early detection using the II technique in a mailed field experiment. The target population was further specified as individuals who had performed this annual test a year earlier and thus are presumed to harbor an intention to carry it out again, as recommended in Israel. One of two instruction versions included in the test kit was mailed to each participant, one offering practical assistance in a detailed “if–then” leaflet addressing frequent barriers (intervention) and the other providing the standard care instruction leaflet (control). Adherence to testing in the two groups was compared. It was hypothesized that the rate of FOBT performance would be significantly higher in the experimental group, as compared to the control group. The possibility of the intervention effects being moderated was examined for cognitive variables (such as attitudes toward the test, self-efficacy, risk perception, CRC knowledge, expressed intensity of intentions); past (testing) behavior; and background variables.