Psychometric Testing of the Spanish Version of the Pain Level Outcome Scale in Hospitalized Patients With Acute Pain José C. Bellido-Vallejo, RN, MSc, María C. Rodríguez-Torres, RN, Isabel M. López-Medina, RN, BSocSc, PhD, and Pedro L. Pancorbo-Hidalgo, RN, BSc, PhD José C. Bellido-Vallejo, RN, MSc, is Operating Room Nurse, University Hospital of Jaen and Assistant Professor in the Department of Nursing, University of Jaen, María C. Rodríguez-Torres, RN, is Nurse in Case Management, University Hospital of Jaen, Isabel M. López-Medina, RN, BSocSc, PhD, is Professor in the Department of Nursing, University of Jaen, and Pedro L. Pancorbo-Hidalgo, RN, BSc, PhD, is Professor in the Department of Nursing, University of Jaen, Jaen.

Search terms: Acute pain, Nursing Outcomes Classification (NOC), validation study Author contact: [email protected], with a copy to the Editor: fl[email protected] The study was funded by the Fundación Pública Progreso y Salud of the Andalusian Public Health Service (Spain), PI-0543–2011.

PURPOSE: This study aims to evaluate the psychometric properties and sensitivity to change of the Spanish version of the Pain Level Outcome Scale. METHODS: This article applied observational longitudinal validation study with patients suffering from acute pain at three hospitals. FINDINGS: The study included 73 patients. Inter-rater agreement was kappa = .88 and internal consistency α = .93. Principal components analysis yielded four components that explained 81.86% of the variance; the correlation with the Numerical Pain Intensity Scale was r = −.81. CONCLUSIONS: The version with 17 indicators shows good psychometric properties and adequate sensitivity to change. A Spanish version of the Pain Level Outcome Scale with 17 indicators is proposed as a structured multidimensional instrument to help nurses choose the most appropriate indicators for assessing patients’ pain.

There is an increasing consensus that pain should be considered as the fifth vital sign (Davis & Walsh, 2004). Acute pain is a common reason for going to the general physician, specialist, or emergency department (Davis & Walsh, 2004). Pain is a frequent symptom in hospitalized patients. Sawyer, Haslam, Robinson, Daines, and Stilos (2008) in Canada found that 71% of adult inpatients in medical and surgical units reported pain, which was severe in 11.4% of the cases. In patients with cancer pain appears during initial, intermediate, and advanced stages. A systematic review (van den Beuken-van Everdingen et al., 2007) found a prevalence of pain in patients with cancer from 33% to 64% as a function of the treatment phase and progression of the disease; with more than 33% of patients rating their pain as moderate/severe. There is some evidence that moderate/severe pain has a negative impact on the emotional and functional well-being of cancer patients (Wells, 2000), which reinforces the importance of pain assessment. Assessment is the first step in the approach to pain, and it is recommended that all individuals at risk be asked about the presence of pain or discomfort (Registered Nurses’ Association of Ontario, 2013). Implementation of systematic pain assessments can be a challenge, but is essential to


determine the intensity and evolution of pain and the effectiveness of treatments (Wells, 2000). For acute pain, it is recommended to evaluate its intensity and other psychological and behavioral aspects using a standardized and validated instrument adapted to the patient population (Registered Nurses’ Association of Ontario, 2013). One instrument available to nurses for the assessment and follow-up of acute pain is the Pain Level Outcome Scale (PLO) (code 2102), defined as “Severity of observed or reported pain” in the Nursing Outcomes Classification (NOC) (Moorhead, Johnson, Maas, & Swanson, 2013). The NOC is considered to be a useful instrument for nurses and other healthcare professionals to evaluate and quantify the health status of patients, caregivers, families, or communities (Moorhead et al., 2013). The psychometric properties of the PLO have been investigated in various settings. Validity and reliability data were first published by the University of Iowa team who developed the NOC taxonomy (Moorhead, Johnson, & Maas, 2003). Keenan et al. (2003) examined the inter-rater reliability, criterion reliability, and sensitivity, in a community setting. Behrenbeck, Timm, Griebenow, and Demmer (2005) examined the inter-rater reliability in a tertiary hospital. Lucena, Holsbach, Pruinelli, Serdotte Freitas Cardoso, and Schroeder Mello (2013) studied the

© 2015 NANDA International, Inc. International Journal of Nursing Knowledge Volume 27, No. 1, January 2016

J. C. Bellido-Vallejo et al. validity of two outcomes included in the NOC (Pain Level and Pain Control), while Maas et al. (2002) presented preliminary reliability and validity results for a group of outcomes, including the PLO. However, validation studies to date have used the English version, and none have been published on the Spanish version of the PLO. Evidence on the reliability and validity of the Spanish version of the PLO is essential for its clinical use in Spanish-speaking populations and for future research purposes. Therefore, the objective of this study was to evaluate the psychometric properties and sensitivity to measuring change in pain level of the Spanish version of the PLO when assessing acute pain in hospitalized patients.

Psychometric Testing of Pain Level Outcome Scale the present study, the Spanish version with 21 indicators was used; it has been culturally adapted and its content previously validated by a group of Spanish pain experts (Bellido-Vallejo, Rodríguez-Torres, López-Medina, & Pancorbo-Hidalgo, 2013). Two 5-point scales were used for scoring indicators, as recommended by Moorhead et al. (2013). For each indicator, the option “Not applicable” was available for nurses to select if needed. Numerical Pain Intensity Scale. The NPIS is a onedimensional instrument with well-established reliability and validity that is recommended for pain intensity assessment (Hjermstad et al., 2011; Summers, 2001). The 11-point version was used.

Methodology Data Gathering Procedure A longitudinal-observational validation study was conducted between June and November 2012 in three public university hospitals (Andalusian Health Service) in the province of Jaen, Spain. Sample Patients’ sample size. A sample size of 46 people was estimated as necessary for the validation study to obtain a precision of 0.2 and confidence level of 95%, based on data previously published by Moorhead et al. (2003), with an inter-rater agreement of 70% (κ = .78). Sampling. A group of 29 nurses (22 females, seven males) was recruited as data collection collaborators from three public hospitals. Inclusion criteria for the nurses were: full-time staff nurses; more than 6 months working in this hospital; and experienced in the care of patients with acute pain. All nurses participating in the study were previously trained by the main researcher and received a pamphlet with detailed information on the data gathering procedure. Next, these nurses recruited a non-probabilistic sample of patients, with a quota of five patients for each participating unit. Inclusion criteria for patients were: (a) age over 18 years, (b) conscious state, (c) capacity to speak and communicate in Spanish, (d) hospital admission for a medical or surgical disease that causes pain. Following the recommendation of the ethical committee, patients with intense pain (≥6 points on the Numerical Pain Intensity Scale [NPIS]) at enrollment were excluded.

For each patient in the study, two nurses in each unit carried out a first pain assessment, scoring the NPIS and each PLO indicator and giving a global PLO score. The nurses jointly conducted the patient interview but were blinded to one another in scoring. Demographic, pain treatment, and clinical data of patients were also gathered. The objective of this initial measurement was to determine the inter-rater agreement and the correlation between NPIS and PLO scores. A second pain assessment was conducted, after a time interval ranging from 45 min to 6 days (depending on the unit), by one of the nurses who had conducted the first assessment, using the same instruments. The objective was to establish if the PLO is sensitive to detecting pain change, regardless of pain treatment received. Ethical Considerations The project was approved by the Research Ethics Committee of Jaén (Spain). Nurses and patients were given detailed information on the project and signed informed consents. Participant anonymity and data confidentiality were guaranteed in accordance with national data protection legislation. Data Analysis A descriptive analysis of the patients and nurses was performed, using frequencies and percentages for nominal variables, and means, standard deviation, and 95% confidence intervals for continuous variables.

Measurements Demographic questionnaire. A data-gathering form was designed specifically for this study to gather demographic and clinical characteristics of the patients and socio-professional data of the nurses. Pain Level Outcome Scale. The PLO is included in the NOC taxonomy (code 2102) (Moorhead et al., 2003, 2013). In

Reliability. Cronbach’s alpha was used to evaluate the internal consistency, considering values > .80 to be very good. Cohen’s kappa with quadratic weighting was used to establish the inter-rater agreement for the PLO scores. Validity. Construct validity related to the underlying conceptual structure of the instrument was studied through principal components analysis (PCA), using varimax rota-


Psychometric Testing of Pain Level Outcome Scale tion. Sample adequacy was evaluated with the Kaiser– Meyer–Olkin index and Bartlett’s sphericity test. The variance of each indicator was established by communalities. The number of components was determined according to the criteria: (a) eigenvalue >1, (b) percentage of variance explained >10%, (c) scree test, and (d) review of the rotated component matrix such that loadings met the condition of >0.6 in one component and .50 are in boldface. a Factor loadings. b Spearman’s r between scores of each indicator and global score of the PLO. c Spearman’s r between scores of each indicator and NPIS score. Score range: 0 = no pain to 10 = unbearable pain. Scores for PLO and NPIS are in opposite directions. d Score based on clinical judgment made by the nurse based on the data obtained in the patient interview using the 21 indicators. e Score obtained by adding the scores of the 17 indicators remaining after principal components analysis. f New indicators proposed by the expert panel in the Spanish version. g Indicators removed from the initial version, final version with 17 indicators. *p < .05.

(κ = .59) (Maas et al., 2002) and those found in other studies (Behrenbeck et al., 2005; Keenan et al., 2003; Moorhead et al., 2003). An even higher inter-rater agreement was found for direct pain measurement with the NPIS (κ = .99). This fact could be explained because NPIS is a one-dimensional instrument, whereas PLO is multidimensional. The multidimensionality of PLO is in accordance with recommendations to measure psychological and behavioral indicators as well as pain intensity (Registered Nurses’ Association of Ontario, 2013). In our validation study, the high random error found in four indicators (diaphoresis, loss of appetite, nausea, and perspiration) indicated that they would not be appropriate for the routine clinical assessment of acute pain, and their removal yielded the final version.


Validity Good criterion validity was obtained using NPIS as the gold standard. NPIS is a tool widely applied by nurses for pain level assessment and is well validated (Hjermstad et al., 2011). The correlation found in our study between the global score of the Spanish version of the PLO and the NPIS score (r = −.81) was higher than those reported in the studies by Maas et al. (2002) (r = .44) and by Keenan et al. (2003) (r = .28), confirming the good concurrent validity. The high correlation found for the global PLO suggests that nurses could assess pain in patients by only scoring the outcome as a whole when it is not feasible to measure the indicators, due to the condition or treatment of the patient. This feature represents a major advantage in the clinical

J. C. Bellido-Vallejo et al.

Psychometric Testing of Pain Level Outcome Scale

setting, as noted by other authors (Keenan et al., 2003). Correlations were higher for the two components related to behavioral and emotional dimensions (pain expressions and intense emotional response) than for those related to the physical dimension (physical response and physiological measurements). It could be thought that the lower correlation for physiological measurements derived from difficulties in interpreting the measurement scale used for these indicators, from 1 (severe deviation from normal range) to 5 (no deviation from normal range). The version of each outcome within the NOC taxonomy includes non-structured indicators that require special efforts by nurses for its selection, applying their professional knowledge and experience, and involving previous consensus agreement in their units to standardize the selection; but nurses sometimes choose only the first two or three indicators in the list. Based on our PCA of the Spanish PLO version, we propose the organization of this outcome into four smaller and more homogeneous groups of indicators, namely: pain manifestations, intense emotional response, physical response, and physiological measurement. The increase in the knowledge of the psychometric properties of indicators, as offered in the present study, allows nurses to base their selection of indicators on scientific evidence, considering the characteristics of their patients, the care conditions, and the availability of measurement instruments. Some indicators, such as reported pain, length of pain episodes, and facial expressions of pain, show an elevated inter-rater agreement and good correlation with NPIS and could therefore be considered as firstchoice indicators, favoring a good assessment of the patients’ experience of pain, more efficient nurse work (especially in situations with a high workload), and improved pain control.

ness to participate. Moreover, they received specific training on the application of the PLO, including guidelines on each of the indicators of this outcome. Hence, larger studies are required to verify the usefulness of the PLO for routine pain assessment in the clinical setting. Furthermore, the sample of patients was small and they were not randomly selected, although their representativeness of hospitalized patients with acute pain was favored by the inclusion of patients from different units from three hospitals.

Sensitivity to Change


According to our results, this Spanish version of the PLO has adequate sensitivity to detect changes in the level of pain experienced by patients. The magnitude of the change between the two pain measurements was similar to the range (0.45 points) reported by Moorhead et al. (2003). It should be borne in mind that the time interval between assessments was short in our study, less than 24 hr in 59.2% of patients, because it was conducted in hospitalized patients with acute pain. However, although the Spanish version of the PLO showed a good capacity to detect an increase or no change in patients’ pain, the evidence was less clear on its capacity to detect a moderate reduction in pain, and further studies in larger samples are required to clarify this aspect.

Behrenbeck, J. G., Timm, J. A., Griebenow, L. K., & Demmer, K. A. (2005). Nursing-sensitive outcome reliability testing in a tertiary care setting. International Journal of Nursing Terminologies and Classifications, 16(1), 14–20. doi:10.1111/j.1744-618X.2005.00002.x Bellido-Vallejo, J. C., Rodríguez-Torres, M. D. C., López-Medina, I. M., & Pancorbo-Hidalgo, P. L. (2013). Adaptación cultural y validación de contenido del resultado «Nivel del dolor» de la Clasificación de Resultados de Enfermería [Cultural adaptation and content validation of the “Pain level” outcome of the Nursing Outcomes Classification]. Enfermería Clínica, 23(4), 154–159. doi:10.1016/j.enfcli.2013.06.004 van den Beuken-van Everdingen, M., de Rijke, J., Kessels, A., Schouten, H., van Kleef, M., & Patijn, J. (2007). Prevalence of pain in patients with cancer: A systematic review of the past 40 years. Annals of Oncology, 18(9), 1437–1449. Davis, M. P., & Walsh, D. (2004). Cancer pain: How to measure the fifth vital sign. Cleveland Clinic Journal of Medicine, 71(8), 625–632. doi:10.3949/ ccjm.71.8.625 Hjermstad, M. J., Fayers, P. M., Haugen, D. F., Caraceni, A., Hanks, G. W., Loge, J. H., . . . Kaasa, S. (2011). Studies comparing numerical rating scales, verbal rating scales, and visual analogue scales for assessment of pain intensity in adults: A systematic literature review. Journal of Pain and Symptom Management, 41(6), 1073–1093. doi:10.1016/j.jpainsymman.2010 .08.016 Keenan, G., Barkauskas, V., Stocker, J., Johnson, M., Maas, M., Moorhead, S., & Reed, D. (2003). Establishing the validity, reliability, and sensitivity of NOC in an adult care nurse practitioner setting. Outcomes Management, 7(2), 74–83.

Limitations One limitation of this study concerns the representativeness of the sample of nurses, given that the selection was based on their experience and especially on their willing-

Conclusions and Practical Implications This study provides evidence of the reliability, validity, and sensitivity to change, of the Spanish version of the PLO. The PLO is a well-structured multidimensional instrument for assessing pain intensity and associated behavioral, emotional, and physical aspects. These data on its psychometric properties offer greater knowledge of the PLO to nurses, allowing them the possibility of using the whole instrument, a single component, or a selection of key indicators, as a function of the type of patient and the protocols in their unit. This research opens the way for further research to increase knowledge of the psychometric properties of the PLO both in Spanish and English-speaking populations. Acknowledgments. The authors are grateful to all the patients in the study for their contributions and to the 29 clinical nurses who devoted effort and time to the patient selection, measurements, and data gathering. They also thank Carmen Rosa Garrido (from Research Foundation for Eastern Andalusia) for statistical advice; Dr. Elizabeth Swanson (from University of Iowa) for critical review and advice; and Richard Davies for assistance with the English translation.


Psychometric Testing of Pain Level Outcome Scale Lucena, A. D. F., Holsbach, I., Pruinelli, L., Serdotte Freitas Cardoso, A., & Schroeder Mello, B. (2013). Brazilian validation of the nursing outcomes for acute pain. International Journal of Nursing Knowledge, 24(1), 54–58. doi:10.1111/j.2047-3095.2012.01230.x Maas, M. L., Reed, D., Reeder, K. M., Kerr, P., Specht, J., Johnson, M., & Moorhead, S. (2002). Nursing outcomes classification: A preliminary report of field testing. Outcomes Management, 6(3), 112–119. Moorhead, S., Johnson, M., & Maas, M. (Eds.). (2003). Nursing outcomes classification (NOC) (3rd ed.). St. Louis, MO: Mosby. Moorhead, S., Johnson, M., Maas, M., & Swanson, E. (Eds.). (2013). Nursing outcomes classification (NOC). Measurement of health outcomes (5th ed.). St. Louis, MO: Mosby-Elsevier.


J. C. Bellido-Vallejo et al. Registered Nurses’ Association of Ontario. (2013). Assessment and management of pain (3rd ed.). Toronto: Author. Retrieved from: bpg/guidelines/assessment-and-management-pain. Sawyer, J., Haslam, L., Robinson, S., Daines, P., & Stilos, K. (2008). Pain prevalence study in a large Canadian teaching hospital. Pain Management Nursing, 9(3), 104–112. doi:10.1016/j.pmn.2008.02.001 Summers, S. (2001). Evidence-based practice part 2: Reliability and validity of selected acute pain instruments. Journal of Perianesthesia Nursing, 16(1), 35–40. doi:10.1053/jpan.2001.20657 Wells, N. (2000). Pain intensity and pain interference in hospitalized patients with cancer. Oncology Nursing Forum, 27(6), 985–991.

Psychometric Testing of the Spanish Version of the Pain Level Outcome Scale in Hospitalized Patients With Acute Pain.

This study aims to evaluate the psychometric properties and sensitivity to change of the Spanish version of the Pain Level Outcome Scale...
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