Key words: cancer pain, assessment, pain measurement, numerical scale, compliance

The most important parameter to be considered when devising a therapeutical strategy against cancer pain is the subjective intensity of the pain: no other evaluation element has been yet found to challenge the importance of the pain intensity.

The assessment of the pain intensity is a substantial part of the patient’s evaluation, for clinical and research purposes: the introduction of a quantitative evaluation of pain intensity in the clinical documentation is presently needed to improve the quality standards of assistance and facilities, but could later be an essential element in crediting ability of structures to supply palliative care.

The choice of the instrument, or measurement scale is to be made among those already proven by research and experience, not forgetting that rather important aspects of the practical utilization of such instruments are still open to research. The most common intensity scales are the visual-analogical (VAS), the numerical (NRS) and the verbal (VRS).

The choice of a measurement instrument and its introduction in routine clinical practice is therefore particularly interesting for the facilities and services of palliative care. Very often these pain measurement methods collect data through the patient’s compilation of forms, questionnaires or pain diaries. Knowing the patient’s compliance to the compilation of such instruments is therefore essential to plan the organization system and to adapt the intervention to the real probability of collecting the foreseen data.

This study analyses the compliance of oncology patients with cancer pain in self-assessing (many times a day), pain intensity scales and the evaluation of the main reasons for not compiling the forms.

All the patients taken in charge from 27/12/2000 to 25/6/2001 by the Consulting Service of the Operation Unit of Rehabilitation and Palliative Care of the Milan Cancer Institute have been considered. Eligible for the study were only the patients complying with all the following inclusion criteria:

Consulting Service of Pain Therapy and Palliative Care

Patients submitted to surgical operations were excluded during the period immediately following such operations, as were patients with heavy pain caused by therapeutic and diagnostic procedures and interventions.

Procedure for measuring pain and evaluating compliance

The assessment of pain intensity was made every day, 5 days a week, during a period of 6 months, by the professional nurse in charge on behalf of the Consulting Service according to the following procedure.

1. At the first visit a daily form of self-assessment was given to the patient with the following explanations:

• method of assessment of the pain score (numerical scale from 1 to 10)
• system of compilation (mean pain during the period of assessment, information on episodes of breakthrough pain (BKP), timing of each assessment)
• utilization of the data listed in the form for evaluation
• organization of distribution and collection of the forms in working days and holidays
• importance of the systematic pain assessment

1. Every day, from Monday to Friday, a new daily form was given to every patient and the form filled with the data of the preceding day was collected. On Fridays the daily forms to be filled on Saturdays and Sundays were given: forms to be collected on Mondays.

The form was set for three daily pain self-assessments on numerical scales from 1 to 10, to be made during morning afternoon and evening. Each time the pain assessment had to be done at rest and on movement.

The patient’s compliance to the assessment was evaluated on a daily basis for each collected form as complete, partial or missing: only at weekends were two forms evaluated together.

3. If a form was partially or totally incomplete the reasons for lack of compilation were discussed in an informal meeting and classified in 10 categories:

Careless omission, pain, depression/interior sickness, worsening of general conditions, lack of motivation, lack of comprehension, lack of will, astheny/physical sickness, lack of pain, other.

These categories were identified during the 3 months preceding the study through systematic observation and registration of the reason why the patients were not doing their self-assessments.

The time elapsed since the first appearance of the pain symptoms was recorded with the basic demographic data (sex, age, years of school attendance, hospital area of origin).

4. Each time, and more frequently upon dismissal, the free opinions of a group of patients (73) about form compilation and pain self-assessment were recorded to make a brief qualitative survey.

In case of non-compilation or partial compilation, a reinforcing activity was provided by the professional nurse to monitor the difficulties faced by the patient and to devise possible solutions (among which was assisted compilation).

The aim was to act above all on the subjective component of the reasons for non-compilation. Support was therefore given above all to patients reporting subjective reasons.

The support activity always included a further explanation of the method, importance and scope of the survey and utilization of data. This activity was developed through meetings and by sometimes being present at the compilation of the forms.

Compliance was defined as the number of completed assessment forms in relation to the maximum number of forms that could be theoretically filled in during the number of evaluation days available for each patient.

Associations between compliance and social-anagraphic available variables was evaluated either through the Krustkall – Wallis test for independent samples or through the Pearson correlation coefficient, according to the nature of the variables (ordinal-categoric or continuous).

For the variables of motivation of the missing data and of evaluation of the support action, a synthesis of the serial data in 1 or more indicators was made for each patient and a detailed description of the type of the synthesis will be made together with the presentation of the results.

Out of 174 patients examined by the organization during 6 months, 106 were eligible for the study and 68 were excluded: 24 because of alterations of their conscience status, 11 because of their refusal to be part of the study, 11 because of their inability to understand and communicate, 9 because of lack of pain and 13 because of other reasons (e. g. observation time too short due to patient’s dismissal or post-operation pain).

The sample of 106 eligible patients was composed of 56 women and 50 men from 19 to 80 years old, with an average of 59 years.

Due to organizational reasons the level of instruction was not recorded for 44% of the cases.

For 59 patients (56% of the total) this information was available: 31% of the total sample had a primary or middle school diploma, 16% a high school certificate, 7.5% a bachelor's degree and only 1% had no educational qualification at all.

Of the 106 patients chosen for the study, 45% came from medical areas and the remaining 59.5% from surgical areas. The patients were followed for an average period of consultancy of 11 days (from 1 to 42 days) for pain problems directly caused by neo-plastic sickness and present on average in the last 2 months.

In 58% of the cases the forms were completely filled in,, in 5% of the cases partially filled in and in 47% of the cases left blank. Out of 106 patients, 25 (23.5%) duly filled in 100% of their forms and 14 (13.2%) never recorded any data on the forms.

To simplify the analysis of the different aspects of non-compilation of the forms, the exceptional cases of partial compilation were considered as a lack of compilation in our further analysis.

The statistical distribution of the compliance is better shown in figure 2 with the box plot method, comparing the compliance of working days, holidays and total. There is no difference in compliance on working days versus holidays.

The analysis of a possible association of compliance with age, sex, area of origin, time from beginning of pain, gave no significant result. A weak inverse association between evaluation days (length of the analysis period) and percentage of days of complete compilation (correlation coefficient – 0.26 p< 0.01) was found: this means that the patients’ compliance lowers as the number of evaluation days grows.

The descriptive analysis of the non-compilation reasons was made on the 81 patients who had at least 1 day of incomplete evaluation. The 10 categories of non-compilation reasons utilized during the data collection were synthesised as follows.

• physical reasons including: pain worsening of general conditions, physical sickness/astheny
• subjective reasons including: careless omission/lack of motivation, lack of will, depression
• lack of pain
• lack of comprehension
• forms not delivered
• other

The longitudinal synthesis of the data related to the classified non-compilation causes was made evaluating each motivation:

• percentage of patients giving the reason at least once
• percentage of patients giving the reason as the main one (this cause is given more often than the other causes)
• the average percentage in the evaluation period and the average number of days when the patients gave the reason as the main one (number of days when the patient gives the reason as the main one related to the total number of days of evaluation).

Table 1 shows the results of the analysis: the main causes are, in order of frequency, subjective and physical reasons and lack of pain. The lack of comprehension of the evaluation method is very marginal.

48% of the patients who did not fill in the forms always gave the same reason for all the blank forms (this is therefore the main reason), 37% declared 2 reasons, 9% declared 3 reasons and 6% declared 4 reasons.

The reinforcing activity, which aimed at improving compliance was performed on 44 patients, whose main cause of unsatisfactory compliance was due to subjective (52%) and physical (32%) reasons, to lack of pain (11.5%) or other (4.5%). In 17 cases reinforcing was given for 1 day only, in 14 cases for 2 days and in 13 cases for 3-5 days.

The short term effectiveness of the reinforcing activity was evaluated with reference to the forms filled in the day after the last day of reinforcing activity: this had a positive result in 44% of the cases, while 56% of the patients did not fill in the forms.

To analyse the long term effect, the percentage of forms filled in by each patient after the support action was considered.

51% of the patients continued not to fillin the forms, 15.5% filled in the forms during 10-33% of the residual period of time after the end of the support action, 15.5% filled in the forms during 60-90% of the said period and 18% filled in the forms every day.

A reinforcing activity could not always be suggested due to the emotional status of the person, to his/her unavailability at the first meeting or to his assistance or clinical needs that made more continuous cooperation difficult or impossible. In fact, 12 patients who did not fill in the forms due to main subjective reasons, could not receive any reinforcing activity: 5 of them because the partial compilation of the forms was due to inability in remembering and 7 of them because of the peculiarity of their emotional and character situations.

73 intermediate and final opinions of the patients on the evaluation methods were collected with the following results:

• 13 patients expressed satisfaction and felt the survey was useful. One Patient kept on recording the scores also at home and delivered the forms during his future visits
• 25 patients felt the survey was not relevant and saw it as an additional burden to their hospitalisation problems. Three of them had lack of pain for a significant period of time, 2 had sight problems and 3 had to remain in bed
• 15 patients felt use of the system to describe their pain was difficult: they preferred to express freely what they were feeling. Four of them felt that determining "average" pain was difficult, but were, however, able to fill in the forms. Two of them had a variety of pains, difficult to synthesise in terms of a score on a form
• 16 patients with a particularly anxious emotional status felt unable to fill in the form properly: 9 of them sought the help of relatives or room-mates
• 4 patients were already aware of the instrument because of their former hospitalisation and they felt it was useful.

Some authors recommend using scales from 0 to 10 to measure pain intensity, during research and clinical practice, for a variety of reasons which include the wider possibility of utilization than verbal scales and because they are more easily comprehensible than visual scales: in any case there is a high statistical association among the measures made by each of the above mentioned scales. But all of these scales require an adequate level of compliance by the patients during the survey.

There is very little data on the compliance of patients with cancer pain in writing diaries or filling in forms containing pain intensity scales. Two studies on outpatients demonstrated high compliance in the compilation of pain diaries. In a study by De Wit pain intensity was assessed twice daily with a numerical scale from 0 to 10 over a 2 _ month period of time and all the data were recorded in a diary: in a study by Mansell the diary was compiled for 4 weeks with 2 daily evaluations on a 5-level verbal scale. .

In the first study compliance was 86%, expressed as the percentage of complete replies in relation to the total number of the possible replies. In the second study compliance was the percentage of patients completing 100% of the evaluations: this compliance oscillated between 80% and 89% during the first 3 weeks, falling to 68% during the fourth week.

These percentages are higher than those obtained in our study, but some important differences must be remembered: the two studies above were controlled, while our study was performed to test the protocol of pain evaluation applied to the clinical routine. Our evaluation is also particularly demanding, being based on 3 daily evaluations for 2 periods of pain (at rest and on movement) and therefore on 6 daily evaluations, against the 2 of the above mentioned studies. Moreover, it differs because it was performed in a hospital environment, with inevitable overlapping with diagnosis and care procedures and with the additional burden for the patient: vice versa the above mentioned studies were performed at the home of each patient. Furthermore, in our study daily evaluation of compliance adds a high degree of precision to the recorded data, versus – for example –weekly analysis of the forms with data referring to the whole week.

The adequacy of compliance depends on the research or clinical finality of the evaluation. A study on chronic non-malignant pains proves that an average of 3 daily evaluations for 4 days out of 7 improves reliability and validity of the data. The level of compliance necessary to optimise the value of the assessment for clinical purposes was not established.

For example, letus suppose we utilize the results of this test to evaluate the amount of data available to clinically monitor the first week since hospitalisation: the data collected show that 30% of the patients supply less than 2 complete evaluations, 21% supply 3 to 4 of them, 29% supply 5 to 6 and only 20% supply all 7 complete evaluations.

Therefore, 70% supply at least 3 evaluations, but it should be verified that this level of compliance sufficiently satisfies the requirements of the clinical validity of the evaluation.

Our observations of the reasons for non-compilation can be evaluated to pre-identify the problems and to try and review the importance in setting the evaluation methods.

The most common reasons for non-compliance are subjective (emotional status and motivation level) and physical.

Non-compliance due to lack of pain is also very interesting: this reason is the third most important cause of non-compilation due to its diffusion and the average number of days when it is chosen.

Therefore, some reasons for non-compliance can be overcome with better education and motivation of the patients while some other reasons, connected to the seriousness of the conditions and to the performance, are not modifiable. The very low significance of lack of comprehension of the method (1.2%) as a cause of lack of compliance must be stressed: this confirms the theoretical simplicity of using numerical scales to quantify the pain for patients who maintain their cognitive functions. The reinforcing activity of the nurse proved to be partially effective for 44% of the patients who filled in the forms the day after the support and for lower percentages of patients enjoying a positive effect for a longer period of time.

The qualitative evaluation of the patients' opinions, carried out on sample of 72 patients, gives us the possibility of understanding some aspects that are relevant for the patients: the additional burden for a hospitalised patient – already physically and emotionally stressed –of compiling scales or subjective questionnaires, the need to give a better description of their pain, but also the usefulness – at least for some of them – of measuring their pain.

Taken together, these observations suggest some possible actions to be developed to make the need for a quantitative evaluation of pain intensity more adequate, useful and comprehensible to the patients and, in addition, to better study the utilization of instruments of subjective evaluation particularly fit for palliative care, their utilization on elderly patients, in advanced stages of sickness with heavy general situations, the lowering of compliance connected to the shortening of prognosis, the interaction with relatives or delegates, the evaluation of patients with reduced cognitive capabilities. .

There are further variables worthy of study: the comparison with other measurement methods or scales, the patient’s motivation through a greater commitment by the doctor during the reinforcing and motivation process and – finally – the influence of the emotional level of the relationship as a motivating system, to verify if the emotional level of the relationship gives some contribution to the success or lack of the patient’s motivation.

Figure 1 Daily pain evaluation form

Morning (from awakening to 12.00 p.m.)

Evaluate your pain by circling the number which better describes its average intensity AT REST in the morning up to now.

0 1 2 3 4 5 6 7 8 9 10

Evaluate your pain by circling the number which better describes its average intensity ON MOVEMENT in the morning up to now.

0 1 2 3 4 5 6 7 8 9 10

Afternoon (from 12.00 to 6.00 p.m.)

Evaluate your pain by circling the number which better describes its average intensity AT REST from 12.00 p.m. up to now.

0 1 2 3 4 5 6 7 8 9 10

Evaluate your pain by circling the number which better describes its average intensity ON MOVEMENT from 12.00 p.m. up to now.

0 1 2 3 4 5 6 7 8 9 10

EVENING (from 6.00 p.m. onwards)

Evaluate your pain by circling the number which better describes its average intensity AT REST from 6.00 p.m. up to now.

0 1 2 3 4 5 6 7 8 9 10

Evaluate your pain by circling the number which better describes its average intensity ON MOVEMENT from 6.00 p.m. up to now.

0 1 2 3 4 5 6 7 8 9 10

TAB. 1 Reasons for not filling in the form