Jacobson and Truax Method: evaluation of the clinical effectiveness of a home care program after prostatectomy 1

ABSTRACT Objective: to exemplify the applicability of the Jacobson and Truax Method in a nursing intervention study that analyzed the effectiveness of a home care teaching program after radical prostatectomy. Method: this is a descriptive study concerning the applicability of the Jacobson and Truax Method in the data analysis of a clinical trial. The intervention consisted of a teaching program for hospital discharge after radical prostatectomy through oral guidance, writing, and telephonic reinforcement. Thirty-four men participated in the intervention group and 34 men participated in the control group. A reliable index of change and clinical significance was calculated for the knowledge variable in both groups. Scatterplots were presented to demonstrate the effectiveness of the method. Results: for 30 individuals in the intervention group, the intervention presented clinically relevant change than in knowledge. In the control group, none of the 34 individuals presented clinical significance of the results related to this variable, that is, the statistical significance identified by the inferential tests did not have clinically relevant changes in the knowledge variable. Conclusion: the educational intervention carried out through the combination of oral, written and telephone counseling was shown to be clinically effective in improving knowledge about home care.


Introduction
Nurses are considered the front-line care professionals and they have great influence on the experiences and outcomes of the clinical evolution of patients. In this sense, the number of studies in the nursing area associated with the actions of nurses and their impact on clinical outcomes (1) has significantly increased in recent years.
However, this number of clinical trials in nursing is still incipient, mainly due to the recent area of activity of the profession and high cost for development (2) . However, it is known that it is an area with important development potential, capable of expanding the professional clinical practice to contribute to the improvement of health care for the population. Authors point to a predominance of this method of study in the area of adult and female health, and a smaller number in the health of the child, elderly, worker, and neonatology (3) .
Regarding methods of analysis of results, there has been an investment in methods and criteria to evaluate the effectiveness of clinical practices in the last decades (3) to identify the really effective procedures, with questions related to the variability of results among participants of the same intervention and the clinical effect of it. Besides identifying the statistically significant differences between individuals, there is a concern to verify the significance and adaptive functionality of the changes brought about by the intervention, which is not necessarily guaranteed by the statistical significance (4)(5) .
The effectiveness of an intervention, whether educational or clinical, implies gathering evidence on the internal validity of the interventions (degree that the results can be attributed to the procedures used) and on social or external validity (impact on the daily functioning of the individual, generalization for other environments or population, cost-benefit ratio) (6) .
In this perspective, several proposals for the analysis of the effectiveness of the interventions, mainly directed to the investigation of the clinical significance of the results obtained (7) appeared. Among them, there are Jacobson and Truax (JT) highlighted (8) , known as the JT Method. This method articulates the analysis of clinical significance with the verification of the reliability of the changes obtained (8) . It can be used as a complement to the analysis of statistical significance when working exclusively with numerical scales. Also, it is considered an alternative method when the number of subjects makes inferential statistical analysis impossible (5)(6) .
Practically, the JT method proposes a comparative analysis of pre and post intervention scores to decide if the differences between the participants represent reliable changes and if they are clinically relevant (4)(5)(6)(7) . Therefore, this method tries to answer two questions: did the gains of the individual go beyond a mere oscillation (positive or negative) due to the measurement error? What is the final condition of the individual in relation to the scores of non-clinical reference groups? Thus, data analysis using the JT Method implies two complementary procedures: the calculation of the reliability of the changes that occurred between the pre-assessment and the post-intervention evaluation, described in terms of a Reliable Change Index (RCI), and the analysis of the clinical significance of these changes (5)(6)(7) .
This study shows the application of this method in a clinical study that evaluated the effectiveness of a teaching program for the home care of patients submitted to radical prostatectomy, to evaluate the operationalization and applicability of the JT Method in nursing intervention research, from the dimensions of self-efficacy, anxiety, psychological morbidity (anxiety plus depression), satisfaction and knowledge.
After radical prostatectomy, patients may have different symptoms, such as fatigue, decreased physical capacity, urinary tract infection and surgical incision, sexual dysfunction and urinary incontinence (9)(10) .
Considering these possible changes after prostatectomy, it was proposed the elaboration of a teaching program based on nursing orientations that improve the knowledge of these individuals about home care, for a greater capacity for self-care, increased satisfaction with care postoperative period and decreased psychological morbidity.
Thus, the objective of this study was to exemplify the applicability of the JT Method in a nursing intervention study that analyzes the effectiveness of the teaching program for home care after radical prostatectomy.

Method
This is a descriptive study regarding the applicability of the JT method in the data analysis of a clinical trial.
The study was carried out in three hospitals in the interior of Minas Gerais from January 2012 to February 2013, with patients undergoing radical prostatectomy who had the following eligibility criteria: age above 18 years old, cognitive ability for participation assessed at application of the mini-mental state examination (11) , locomotor, visual, auditory and self-care skills, and telephone to follow up on the teaching program.
Participants were randomly divided into two groups: Control Group (CG) and Intervention Group (IG).
The sample size was estimated considering the expected difference between CG and IG for selfefficacy, after treatment (12) , at a significance level of 5%, and power of 80%, resulting in 33 individuals in each group.
It was approved by the Research Ethics Committee The intervention consisted of a teaching program for hospital discharge, elaborated from the combination of oral orientation, writing, and telephonic reinforcement.
A booklet called "Guidelines for home care: Prostate Radical Surgery" was developed, and a script based on the Theory of Self-efficacy (13) was developed to guide the telephone calls in clarifying doubts and reinforcing the guidelines contained in the booklet, stimulating self-care.
The study was developed in four steps in a two-month follow-up. In T0, sociodemographic and clinical variables, self-efficacy, anxiety, psychological morbidity, satisfaction with post-operative care and knowledge were collected; randomization of participants in two IG (n=34) and CG (n=34) groups; and the beginning of the intervention with booklet delivery and oral guidance. In T1, the first telephone call was made between the third and fifth postoperative day; and in T2, the second telephone call was 30 days after discharge. Two months after T0, in the second medical return, the variables selfefficacy, anxiety, psychological morbidity, knowledge, and satisfaction in both groups were measured (T3). It should be emphasized that the CG continued in usual hospital discharge from the health service, without any intervention of the research.
When comparing the variables in the IG with the CG in the post-test, significant differences between the groups for satisfaction (p ≤ 0.001) and knowledge (p ≤ 0.001 ) were identified from inferential tests (parametric and non-parametric).
Thus, to verify if the dependent variables that presented statistical significance by the inferential tests also presented clinical significance, the JT Method was used. Based on the assumption that the JT Method is applicable for numerical scales, the RCI and clinical significance proposed by Jacobson and Truax (8) were From the calculation of RCI, the following parameters are considered (8)

Results
From the use of the JT method in a clinical intervention study, consisting of a teaching program in the home care of patients submitted to radical prostatectomy, the effectiveness of its use was verified.
In presented a reliable negative change, most of them (n=28) were located between the traces above and below the bisector, that is, they did not improve or worsen the knowledge, and six of the participants (S1, S14, S26, S28, S30, S34) showed a positive change in knowledge ( Figure 2).   For example, if a large sample size study has a small standard error, it is easier to find small and unimportant effects for treatment that is statistically significant (5) .
Therefore, when a clinical trial presents a statistically significant difference in its variables, one should also consider whether it is clinically important and large enough to merit a change in practice (16)(17) .
Thus, it was possible to answer the two questions in this study based on RCI analyzes and clinical significance (8) . In IG, only two of the 34 individuals did that these effects bring to men and their caregivers (19) .
The JT Method articulates the analysis of clinical significance (more focused on external validity) with verification of the reliability of the changes obtained (more related to internal validity) (4,17) . In this study, Therefore, such tests have little information about the clinical significance of these differences (5,16) .
In the literature, some clinical research that used the JT Method for the treatment of the data in recent years were identified. There is a study highlighted that compared the performance of the JT Method with three other alternative methods to determine which one best measured the changes in treatment ratings for substance use disorders (20) . Another study evaluated an intervention program for hypertensive patients, according to the variables knowledge, skills for selfcare, therapeutic adherence, coping strategies and stress management (17) , and other researchers discussed possible statistical analyses based on the relationship between RCI and clinical significance in the context of intervention for the improvement of speech and language disorders (5) . Finally, a study that verified the use of methods to quantify the clinical significance of the change during participation in an intervention program for alcohol and drug prevention was identified (21) .
In education, the JT Method has also been applied.
Researchers used it to assess the progress of medical undergraduates in learning best practices and identified the major errors made by students (16) . More specifically in special education, scholars evaluated RCI and clinical significance for the results of a group of mentally retarded adults who participated in a program to promote social and communicative skills (22) . Also in special education, the effects of a phonological remediation program with eight regular students diagnosed with Down Syndrome (23) were verified using the JT method.
Regarding the use of clinical significance in primary nursing studies, a review of the literature with the objective of analyzing the advances of the topic in the area (24) (25) .
Therefore, it is expected that the JT Method will offer sufficient advantages for its use in clinical change assessment research, and that may eventually be used by is expected that this work will contribute to disseminate the potential of this method and stimulate researchers and professionals for its use in clinical nursing research.