The development and validation of the Pre-operative Intrusive Thoughts Inventory (PITI)

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1 doi: /j x The development and validation of the Pre-operative Intrusive Thoughts Inventory (PITI) J. K. Crockett, 1 A. Gumley 2 and A. Longmate 3 1 Chartered Clinical Psychologist, Child and Adolescent Mental Health Service, NHS Forth Valley, The Manor, Brown Street, Camelon FK1 4PX, UK 2 Senior Lecturer in Clinical Psychology, Section of Psychological Medicine, Division of Community Based Sciences, University of Glasgow, Academic Centre, Gartnavel Royal Hospital, 1055 Great Western Road, Glasgow G12 0XH, UK 3 Consultant Anaesthetist, Department of Anaesthesia, NHS Forth Valley, Stirling Royal Infirmary, Livilands FK8 2AU, UK Summary Pre-operative anxiety is common and influences postoperative pain, hospital stay and patient satisfaction. We set out to explore anxiety content and develop a tool to evaluate patient anxiety at the pre-operative assessment clinic. We recruited 128 day surgery patients. Pre-operative anxiety content was explored and six factors (themes) were identified: preoccupation, outcome concerns, being unconscious, loss of control, dependence on others and pain discomfort. The Pre-operative Intrusive Thoughts Inventory (PITI) was constructed and evaluated using exploratory and confirmatory factor analysis. The PITI demonstrated internal consistency for the full scale (Cronbach s a = 0.91) and for the subscales (Cronbach s a ) as well as sensitivity (0.88) and specificity (0.60) to clinically significant anxiety assessed using the Hospital Anxiety and Depression Scale. The properties of the PITI suggest that it has potential as an additional tool for the evaluation of pre-operative anxiety.... Correspondence to: Dr A. Longmate alongmate@nhs.net Accepted: 5 March 2007 Pre-operative anxiety is a common problem [1 3]. It has been associated with increased postoperative pain, analgesic requirements, length of stay, distress and disability [1, 4 10]. Opportunities for anaesthetists to see patients before the day of surgery are being reduced by the increase in day surgery and day of surgery admissions. Teams may have less time to prepare patients and preoperative anxiety may go undetected [11, 12]. An objective tool to assess anxiety level and content might be a useful addition to the patient review process at a nurse-delivered pre-operative assessment clinic. Existing measures of pre-operative anxiety all have limitations. The state component of the STAI (Spielberger State- Trait Anxiety Inventory) (STAI-state) has been used previously in the pre-operative setting [2, 13], but is a measure of state anxiety (anxiety about the situation that the patient is currently in) and does not specifically pertain to pre-operative anxiety. The Yale Preoperative Anxiety Scale (YPAS) [14] was designed specifically to assess anxiety in children during the induction of anaesthesia. The Amsterdam Preoperative Anxiety and Information Scale (APAIS) [13, 15] is a simple six-item questionnaire. This measure has a number of important strengths. It shows good internal reliability and its brevity enables rapid administration. It has been found to have a simple two-factor structure: Anxiety (four items) and Need for Information (two items). The Anxiety subscales show moderate to good sensitivity (53 75%) and strong specificity (79 97%) for clinically significant anxiety. However, the brevity of the measure does not enable the identification of specific concerns reported by patients prior to surgery, which may be numerous and wide ranging. For example, pre-operative patients have intrusive thoughts relating to aspects of their impending procedure, the general anaesthetic, the outcome of surgery, the possibility of pain or discomfort and being unconscious [12, 16, 17]. Intrusive thoughts may cause an increase in patients anxiety and patients may experience clinically significant behavioural, emotional, cognitive and physiological changes. For example, patients with Journal compilation Ó 2007 The Association of Anaesthetists of Great Britain and Ireland 683

2 J. K. Crockett et al. Æ Pre-operative Intrusive Thoughts Inventory high levels of pre-operative intrusive thoughts may also show increased avoidance behaviour, have greater focus on their bodies, greater health-related worry, more preoccupation and more frequent re-assurance seeking. We set out to explore the content of pre-operative anxiety and to develop and validate a simple self-rating measure to be used at the pre-operative assessment clinic which would allow rapid assessment of pre-operative anxiety. Methods Approval for the investigation was obtained from the local ethics committees. Potential participants were informed of the study by an information sheet enclosed with their pre-operative assessment clinic appointment letter. One investigator (JKC) attended a weekly gynaecology and day surgery pre-operative assessment clinic over a 4-month period. Patients were approached by JKC when they arrived at the appointment and asked to consider entering the study. A private room was used to recruit all participants and to conduct the interviews. Written informed consent for the study was obtained for all participants at the clinic before they entered the study. The study comprised a pilot phase and a main phase. The pilot phase involved the construction of a 24-item Pre- Operative Intrusive Thoughts Inventory. During the main phase of the study, the structure of the PITI-24 was empirically investigated with factor analysis using principal components analysis. This created a final twenty-item Pre-Operative Intrusive Thoughts Inventory ( PITI-20 ) (Appendix 1). The PITI-20 was assessed for internal consistency, predictive validity, concurrent validity and discriminant validity. Pilot phase (item development and PITI construction) Prior to the main investigation, a pilot phase was conducted with the aim of confirming whether the previously identified commonly expressed fears of patients were experienced by these participants and to identify any other areas of concern, thereby generating items for the PITI. Previous studies examining the content of pre-operative anxiety have generated four specific themes: the general anaesthetic, the outcome of surgery, the possibility of pain or discomfort, and being unconscious [12, 16, 17]. Eight patients six female and two male, mean age 52 [range 31 75] years were recruited and given a semistructured interview comprising general questions about the participant and the nature of their surgery, open-ended questions regarding the occurrence and nature of any pre-operative anxiety, and direct questions probing specific areas of pre-operative anxiety. All comments regarding participants anxieties were noted verbatim and collated. The accuracy of the recorded responses was checked with the participants at the end of their interview. All patient responses were explored. Responses were discarded if they were idiosyncratic to an individual s particular situation. The content of the comments was collapsed into five themes: 1) anticipatory anxiety and pre-occupation ; 2) outcome results ; 3) control dependence ; 4) pain discomfort ; and 5) anaesthetic. AG and AL were asked independently to allocate all patient comments into one of these five themes (they were blinded to the initial allocation). There was consensus between the three investigators with more than 95% of comments allocated to the same themes. These five themes were then used to generate 20 items, four items per theme. Each item had a four-point Likert scale directed response anchored by Not at All and All of the time. As worries about being unconscious had been identified in previous studies as a pre-operative fear, this was added as a sixth theme (with four questions). This created a six-theme, 24-item inventory ( the PITI-24 ), which was used as a basis for the main part of the investigation. The six themes were: 1) anticipatory anxiety and pre-occupation ; 2) outcome results ; 3) control dependence ; 4) pain discomfort ; 5) anaesthetic ; and 6) being unconscious. Main investigation A total of 142 patients listed for elective minor day surgery were approached to participate in the study during their attendance at nurse-led pre-operative assessment clinics. Thirteen patients declined to participate and one patient was excluded because of an insufficient understanding of the English language. Eight patients took part in the pilot phase and 120 patients participated in the main part of the study. The following information was recorded: age, gender, the subspeciality of surgery being undertaken, and whether the procedure was investigative or non-investigative. For example, a laparoscopy to assess abdominal pain or potential disease was classed as investigative; a laparoscopy for tubal ligation was classed as non-investigative. Participants were asked to complete the PITI-24 and two other measures: The Health Anxiety Questionnaire (HAQ) [18], and The Hospital Anxiety and Depression Scale (HADS) [19]. The Health Anxiety Questionnaire (HAQ) is a 21-item questionnaire, using a four-point Likert scale, developed to identify individuals with high levels of concern about their health. The HAQ has a four-factor structure: 1) worry and health pre-occupation; 2) fear of illness 684 Journal compilation Ó 2007 The Association of Anaesthetists of Great Britain and Ireland

3 J. K. Crockett et al. Æ Pre-operative Intrusive Thoughts Inventory and death; 3) reassurance seeking behaviour; and 4) extent to which symptoms interfere with a person s life. The scale shows good reliability and validity. The Hospital Anxiety and Depression Scale (HADS) is a 14-item questionnaire specifically developed for use with physically ill patients. The HADS is a reliable, valid and easily administered tool for identifying and quantifying the two most common forms of psychological disturbance in medical patients: anxiety and depression. All items are scored on a four-point scale. The HADS comprises two factors: anxiety and depression. The scale shows good reliability and validity. Factor analysis of the PITI 24 EQS for Windows (Version 6.1) [20] was used to perform a factor analysis to test the goodness of fit of the originally proposed six-theme (or factor) 24-question PITI-24 structure developed in the pilot phase. There are three primary analyses which examine the goodness of fit of a proposed structure. These are the comparative fit index (CFI), the root mean square error of approximation (RMSEA) and the Chi-square significance [21]. A comparative fit index of greater than 0.90, a nonsignificant Chi-square and a root mean square error of approximation (RMSEA) less than 0.1 are considered to represent a good fit of a proposed solution [21]. The analysis of the proposed six-factor, 24-item PITI produced a comparative fit index of 0.80 (v 2 = 545.6, df = 237, p < 0.001, RMSEA = 0.10). This was not a satisfactory fit between the proposed structure and the actual data, and this structure was therefore rejected. An exploratory factor analysis was conducted on the PITI-24 using principal components analysis, with oblique rotation. Items were removed if their Eigen value loading on factors was less than 0.60 [22]. Four questions had Eigen values less than 0.6. The four items removed were: I worry about being awake during the surgical procedure ; Thoughts and images about the surgical procedure pop into my head ; I worry about how I will feel when I am getting the anaesthetic ; and I worry about any side-effects of the anaesthetic. Removal of the four questions from the PITI-24 created a shorter 20-question measure, the PITI-20 (Appendix 1). The removal of four questions did not affect the overall factor structure of the measure as judged by the researchers and the factor analysis. That is, their removal did not remove any particular theme from the questionnaire or upset the internal consistency of the measure as tested below. A summary of the item-to-factor loadings is contained in Table 1. To provide an empirical validation of this factor solution and to test the goodness of fit of the factor solution, a confirmatory factor analysis was then conducted on the revised 20-item, six-factor solution. This produced a comparative fit index (CFI) of (values exceeding 0.90 are considered to be a good fit), demonstrating good overall agreement between the model and the data collected. The Chi-squared test of overall model fit was significant (v 2 = , p 0.001). The Chi-square test is extremely sensitive, with small variations in fit resulting in statistically significant and sizeable Chi-square [23]. Therefore, the best guide to the validity of factor structure of the PITI can be derived from the CFI and RMSEA values. The RMSEA value for the PITI was 0.08, further confirming the six-factor, 20-item structure of the PITI, the PITI-20. The remaining 20 items were studied for factor content and factor headings were agreed between the researchers. All questions had earlier been divided into separate themes as described previously. The final version of the PITI (PITI-20) comprised the following six factors (or themes): pre-occupation, outcome concerns, being unconscious, loss of control, dependence on others, and pain discomfort. Two of the factors contained four items ( being unconscious, pre-occupation ) and the remaining four factors contained three items each. To investigate the reliability of the PITI, Cronbach s alpha was calculated. Cronbach s alpha for the PITI-20 = 0.91 (95% CI = ). The Cronbach s alpha for each of the six factors was as follows: being unconscious = 0.85 (95% CI = ), pre-occupation = 0.84 (95% CI = ), outcome concerns = 0.74 (95% CI = ), pain discomfort = 0.85 (95% CI = ), dependence on others = 0.84 (95% CI = ), loss of control = 0.75 (95% CI = ). Item loadings ranged from 0.60 to Results Of the 120 patients who participated in the main part of the study, 93 (77.5%) were female and 27 (22.5%) were male. The mean age was 42.5 (range 20 83) years. Patient number distribution between different surgical subspecialities was as follows: gynaecology 75, orthopaedic 25, general surgery 16, dental surgery 4; 54 patients (45%) were listed for investigative procedures, 66 (55%) for non-investigative procedures. Table 2 summarises the Spearman correlations between the PITI-20 subscales. All correlations between subscales were statistically significant at the p < 0.01 level. Being unconscious correlated particularly strongly with preoccupation (r rho = 0.608) and Loss of Control (r rho = 0.580). Pre-occupation correlated particularly strongly with Outcome concerns (r rho = 0.567). Pain and discomfort correlated strongly with concerns about Dependence on others (r rho = 0.430). Journal compilation Ó 2007 The Association of Anaesthetists of Great Britain and Ireland 685

4 J. K. Crockett et al. Æ Pre-operative Intrusive Thoughts Inventory Table 1 Rotated factor loadings of the PITI items. Loading on factors Item Scale Factor 1: Unconscious I worry that I won t wake up I worry about being unconscious I worry about surgical complications I worry about how long I will be unconscious for Factor 2: Pre-occupation Waiting for the surgical procedure makes me nervous I worry about what they are going to find I keep thinking about the surgical procedure when I m on my own I am pre-occupied by thoughts of having the surgical procedure Factor 3: Outcome I worry about the time it will take to get the results I worry about the outcome of the surgical procedure I worry about feeling sick or fainting Factor 4: Pain discomfort I worry about how sore I will be afterwards I worry about how long the pain will last I worry that I may feel uncomfortable when I wake up Factor 5: Dependence on others I worry that I will have to rely on others I worry that I will have to call on people to help me I worry that I won t be able to do things for myself after the surgical procedure Factor 6: Control The thought of having the procedure makes me feel out of control I worry about things happening during the procedure that I will not be aware of I worry that something may be done when I am unconscious that I haven t agreed to Table 2 Spearman s rho correlations between PITI factors and HADS subscales. Factor 1 Factor 2 Factor 3 Factor 4 Factor 5 Factor 6 Anxiety Depression Factor 1 Being unconscious r 0.608** 0.481** 0.287** 0.324** 0.580** 0.535** 0.201* Significance < < < < < Factor 2 Pre-occupation r 0.608** 0.567** 0.316** 0.250** 0.405** 0.582** 0.224* Significance < < < < < Factor 3 Outcome concerns r 0.481** 0.567** 0.291** 0.414** 0.438** 0.441** 0.299** Significance < < < < < Factor 4 Pain discomfort r 0.287** 0.316** 0.291** 0.430** 0.371** 0.391** 0.211* Significance < < < < Factor 5 Dependence on others r 0.324** 0.250** 0.414** 0.430** 0.439** 0.388** 0.378** Significance < < < < < < Factor 6 Loss of control r 0.580** 0.405** 0.438** 0.371** 0.439** 0.453** 0.198* Significance < < < < < < HADS Anxiety r 0.535** 0.582** 0.441** 0.391** 0.388** 0.453** 0.594** Significance < < < < < < < HADS Depression r 0.201* 0.224* 0.299** 0.211* 0.378** 0.198* 0.594** Significance < < **Correlation is significant at the 0.01 level (2-tailed). *Correlation is significant at the 0.05 level (2-tailed). r, correlation coefficient; n = 120 for all correlations. 686 Journal compilation Ó 2007 The Association of Anaesthetists of Great Britain and Ireland

5 J. K. Crockett et al. Æ Pre-operative Intrusive Thoughts Inventory Anxiety and Depression The Spearman correlation coefficient between the PITI- 20 total score (the sum of the numerical values (0 3) for each of the 20 PITI questions see Appendix 1) and HADS (Anxiety Subscale) was r rho = 0.69, p < 0.01, and with the HADS (Depression Subscale) was r rho = 0.39, p < As expected, the PITI-20 subscales all correlated strongly with the HADS (Anxiety Subscale) (Range (see Tables 1 and 2)). Using a PITI-20 cut-off score of 15 and a HADS anxiety score of 11 [24] as the score for moderate-severe anxiety [25], the area under the ROC curve was significant (0.84, CI = , p = 0.00, sensitivity = 0.88, specificity = 0.60). Thus the true positive rate for the PITI-20 (score 15) against the HADS (anxiety score 11) was 87.5%, and the true negative rate was 60%. Fifteen percent (n = 18) of the sample met criteria for moderate-severe anxiety [25] as defined by a HADS anxiety score of 11. Health Anxiety Table 3 shows the Spearman correlations between the PITI-20 and the Health Anxiety Questionnaire (HAQ). The PITI-20 (total score) significantly correlated with the HAQ (total) r rho = 0.540, p < The PITI-20 factors to HAQ (total) ranged from r rho = The HAQ (Subscales) to PITI-20 total correlations ranged from r rho = , with the highest correlations seen with the Health Worry and Pre-occupation subscale Table 3 Spearman s correlations between PITI factors and HAQ factors. (r rho = 0.489, p < 0.01) and Fear of Illness and Death subscale (r rho = 0.508, p < 0.01). Discriminant validity Fifty-four participants were scheduled to undergo investigative procedures (n = 54, mean PITI-20 score = 17.83, SD = 11.63) and 66 participants were scheduled to undergo non-investigative procedures (n = 66, mean = 13.64, SD = 9.97). The difference between the group means was significant (t = 2.13, df = 118, p = 0.04; Cohen s d = 0.39) [26]. Discussion This study has further defined pre-operative anxiety content and represents the preliminary stages of development of the The Pre-operative Intrusive Thoughts Inventory ( the PITI ); a tool designed to assess preoperative anxiety. The following six factors (or subscales) of anxiety were identified: Pre-occupation, Outcome Concerns, Being unconscious, Loss of control, Dependence on others, and Pain discomfort. The psychometric properties of the PITI suggest that the measure might have potential as an addition to existing tools used for the assessment of pre-operative anxiety. The measure appears to be reliable and valid and demonstrates good internal consistency as measured by Cronbach s alpha. The PITI-20 demonstrated promising Health worry and pre-occupation Fear of illness and death Re-assurance seeking behaviour Interference with life HAQ total PITI total Correlation co-efficient 0.489** 0.508** 0.286** ** Significance 2-tailed < < < Factor 1 Being unconscious Correlation co-efficient 0.381** 0.470** 0.256** ) ** Significance 2-tailed < < < Factor 2 Pre-occupation Correlation co-efficient 0.330** 0.387** 0.248** ** Significance 2-tailed < < < Factor 3 Outcome Correlation co-efficient 0.327** 0.363** 0.228* ** Significance 2-tailed < < < Factor 4 Pain discomfort Correlation co-efficient 0.371** 0.327** 0.194* ** Significance 2-tailed < < < Factor 5 Dependence on others Correlation co-efficient 0.370** 0.298** * 0.379** Significance 2-tailed < < Factor 6 Loss of control Correlation co-efficient 0.257** 0.365** 0.186* ** Significance 2-tailed < **Correlation is significant at the 0.01 level (2-tailed). *Correlation is significant at the 0.05 level (2-tailed). r, correlation co-efficient; n = 120 for all correlations. Journal compilation Ó 2007 The Association of Anaesthetists of Great Britain and Ireland 687

6 J. K. Crockett et al. Æ Pre-operative Intrusive Thoughts Inventory sensitivity and specificity for clinically significant anxiety using the HADS Anxiety Subscale. A score of 15 or more on the PITI-20 reliably detected patients who reached clinically significant anxiety as defined by the HADS. The PITI correlated strongly with the Health Anxiety Questionnaire. Specifically, the HAQ to PITI correlations demonstrate that surgical patients experience levels of anxiety regarding health worry and pre-occupation; fear of illness and death; and interference with life. Patients undergoing investigative procedures had significantly higher scores than those scheduled for noninvestigative procedures. Investigative procedures might cause patients to experience a greater frequency of intrusive thoughts before surgery due to the additional uncertainties being faced. We cannot conclude that there is a difference in anxiety levels between these groups as this was not the principal end point of the study and we did not control for confounding factors Participants were scheduled for day surgery procedures and the sample included more women than men due to the large numbers of patients listed for gynaecological surgery who agreed to participate. The reliability and validity of the PITI is yet to be established in other surgical groups and the tool requires further validation with larger samples and a wider range of patients before it could be practically applied at the pre-assessment clinic. References 1 Ramsay MAE. A survey of pre-operative fear. Anaesthesia 1972; 27: Oldham M, Moore D, Collins S. Drug patient information leaflets in anaesthesia: effect on anxiety and patient satisfaction. British Journal of Anaesthesia 2004; 92: Mackenzie JW. Day case anaesthesia and anxiety: a study of anxiety profiles amongst patients attending a day bed unit. Anaesthesia 1989; 44: Augustin P, Hains AA. Effect of music on ambulatory surgery patients preoperative anxiety. AORN Journal 1996; 63: Johnston M, Ögele C. Benefits of psychological preparation for surgery: a meta-analysis. Annals of Behavioural Medicine 1993; 15: Manyande A, Berg S, Gettins D, Stansford C, Mazhero S, Marks DF, Salmon P. Preoperative rehearsal of active coping imagery influences subjective and hormonal responses to abdominal surgery. Psychosomatic Medicine 1995; 57: Manyande A, Salmon P. Effects of pre-operative relaxation on post-operative analgesia: Immediate increase and delayed reduction. British Journal of Health Psychology 1998; 3: Markland H, Hardy L. Anxiety, relaxation and anesthesia for day-case surgery. British Journal of Clinical Psychology 1993; 32: Williams JGL, Jones JR. Psychophysiological responses to anaesthesia and operation. Journal of the American Medical Association 1968; 203: Nelson FV, Zimmerman L, Barnason S, Nieveen J, Schmaderer M. The relationship and influence of anxiety on postoperative pain in the coronary artery bypass graft patient. Journal of Pain and Symptom Management 1998; 15: Kindler CH, Harms C, Amsler F, Ihde-Scholl T, Scheidegger D. The visual analogue scale allows effective measurement of preoperative anxiety and detection of patients anaesthetic concerns. Anesthesia and Analgesia 2000; 90: Mitchell M. Nursing intervention in pre-operative anxiety. Nursing Standard 2000; 14: Boker A, Brownell L, Donen N. The Amsterdam preoperative anxiety and information scale provides a simple and reliable measure of preoperative anxiety. Canadian Journal of Anaesthesia 2002; 49: Kain Z, Mayes L, Cicchetti D, et al. A measurement tool for pre-operative anxiety in children: the Yale preoperative anxiety scale. Child Neuropsychology 1995; 1: Moerman N, van Dam F, Muller M, Oosting H. The Amsterdam Preoperative Anxiety and Information Scale (APAIS). Anesthesia and Analgesia 1996; 82: Mitchell M. 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British Journal of Clinical Psychology 2002; 40: Warwick HMC, Salkovskis PM. Hypochondriasis. Behaviour, Research and Therapy 1990; 28: Fabbri S, Kapur N, Wells A, Creed F. Emotional, cognitive, and behavioural characteristics of medical outpatients a preliminary analysis. Psychosomatics 2001; 42: Appendix 1: Pre-operative Intrusive Thoughts Inventory ( The PITI or PITI-20 ) Many people experience anxiety and worrying thoughts before having an operation. We are interested in the thoughts that you have been having about your planned surgical procedure in the last 2 weeks. 688 Journal compilation Ó 2007 The Association of Anaesthetists of Great Britain and Ireland

7 J. K. Crockett et al. Æ Pre-operative Intrusive Thoughts Inventory Please read the following statements and indicate how often the statement has applied to you, by circling the appropriate number. Do not spend too much time thinking about each one. not at all some of the time often most of the time 1 I worry that I won t wake up Waiting for the surgical procedure makes me nervous I worry about the time it will take to get the results I worry about how sore I will be afterwards I worry that I will have to rely on others The thought of having the procedure makes me feel out of control I worry about being unconscious I worry about what they are going to find I worry about the outcome of the surgical procedure I worry about how long the pain will last I worry that I will have to call on people to help me I worry about things happening during the procedure that I will not be aware of I worry about surgical complications I keep thinking about the surgical procedure when I m on my own I worry about feeling sick or fainting I worry that I may feel uncomfortable when I wake up I worry that I won t be able to do things for myself after the surgical procedure I worry that something may be done when I am unconscious that I haven t agreed to I worry about how long I will be unconscious for I am pre-occupied by thoughts of having the surgical procedure Thank you for your time. Journal compilation Ó 2007 The Association of Anaesthetists of Great Britain and Ireland 689