Cardiac Depression Scale: Mokken scaling in heart failure patients
© Ski et al.; licensee BioMed Central Ltd. 2012
Received: 30 August 2012
Accepted: 16 November 2012
Published: 23 November 2012
There is a high prevalence of depression in patients with heart failure (HF) that is associated with worsening prognosis. The value of using a reliable and valid instrument to measure depression in this population is therefore essential. We validated the Cardiac Depression Scale (CDS) in heart failure patients using a model of ordinal unidimensional measurement known as Mokken scaling.
We administered in face-to-face interviews the CDS to 603 patients with HF. Data were analysed using Mokken scale analysis. Items of the CDS formed a statistically significant unidimensional Mokken scale of low strength (H<0.40) and high reliability (Rho>0.8).
The CDS has a hierarchy of items which can be interpreted in terms of the increasingly serious effects of depression occurring as a result of HF. Identifying an appropriate instrument to measure depression in patients with HF allows for early identification and better medical management.
KeywordsCardiac Depression Scale Heart failure Depression Mokken scaling
Cardiac Depression Scale
American Heart Association
Mokken scaling analysis
Mokken scaling analysis for polytomous items
Invariant item ordering
Statistical Package for the Social Sciences.
Heart failure (HF) is a leading cause of morbidity and mortality worldwide that imposes a considerable human and economic burden [1–4]. Depression and depressive symptoms are common in patients with HF though estimates of prevalence vary depending on method and timing of assessment [5, 6]. A meta-analytic review on depression in HF reported clinically significant depression in 21.5% of patients, but varied by use of questionnaires versus diagnostic interview and HF severity . Accurate identification of depression in patients with HF is critical because of significant associations with increased hospitalisations [5, 7, 8], poorer functional limitations [9, 10], lower survival rates [8, 11, 12], and reduced quality of life . Despite an American Heart Association (AHA) advisory recommending depression screening for all patients with coronary heart disease , depression remains under recognised and under treated in this population . Given the potential health consequences of untreated comorbid HF and depression, the value of using reliable and valid instruments to measure depression cannot be underestimated. This is paramount when one considers the numerous indirect costs of depression such as absenteeism, decreased productivity, increased risk for secondary complications, and malignant effects on dependent family members [16, 17].
Recognition of depression in patients with HF is complicated by an overlap in risk factors such as smoking, excessive alcohol consumption, obesity, and lower physical activity, and symptoms such as fatigue, lack of interest in activities, appetite gain or loss, psychomotor impairment, poor concentration, and depressed mood [1, 18]. These similarities have the potential to result in contrasting outcomes such as screening for depression generating a number of false positive results, and depression remaining undiagnosed for a substantial period of time. Hence, accurate assessment of depression in patients with HF is necessary to aid early intervention.
The AHA advisory endorsing depression screening, referral, and treatment of all individuals with coronary heart disease  has provoked considerable debate [19–23], with much of the contention surrounding the lack of evidence regarding the choice of instruments to measure depression, specifically their psychometric properties. Of note, is that depression screening will only identify depressive symptoms, i.e. those at risk of depression, as a diagnosis of depressive illness can only be confirmed when a person has a number of depressive symptoms consistently over a couple of weeks or more.
The Cardiac Depression Scale (CDS) was developed for the specific purpose of providing a valid and reliable instrument to measure depression in cardiac patients . The CDS is the only measure for depression derived from responses of cardiac patients. It offers a more responsive and sensitive alternative to other measures that are not always suitable for cardiac patients because they have been developed and validated in non-cardiac populations . It is an easily administered (taking five minutes to complete and one minute to score) disease-specific, self-rating scale that assesses the full range of depression seen in cardiac patients. Whilst having 97% sensitivity and 85% specificity for diagnosing major depression, it also assesses the range of less severe ‘reactive’ depression . Validation studies have applied the CDS to a general cardiac population and encouraged its continued use and evaluation in other cardiac patient groups [27–29]. Thus, we aimed to validate the CDS in patients with HF using Mokken scaling analysis (MSA), a method related to item response theory that analyses multivariate databases for unidimensional hierarchies of items .
A unidimensional hierarchy of items can be identified using Loevinger’s coefficient (H) along with other indicators of reliability, probability and monotone homogeneity of items . Recent versions of software for MSA are capable of analysing for invariant item ordering (IIO) , an important property of questionnaires whereby, for a set of items displaying IIO, every respondent responds to all of those items in exactly the same order in the hierarchy . IIO is not necessary for the utility of a questionnaire showing a Mokken scale of items: unidimensionality and monotone homogeneity are sufficient as such a scale can be used to order individuals. However, IIO is desirable. Mokken scaling has recently been applied to several scales designed to measure psychological morbidity and other phenomena [34–36]. We investigated if a hierarchy of items, according to Mokken scaling criteria, existed in the CDS when applied to patients with HF. This paper contributes to a series of validation papers [34–38] that have implemented MSA to determine scale item unidimensional hierarchy.
Summary characteristics of heart failure patients (n=603)
Valvular & RHF
The study was approved by the institutional Human Research Ethics Committee (Approval No. H2006/02657). Written informed consent was obtained from the participants.
The CDS is a 26 item questionnaire, each item requiring a response on a Likert scale from 1 (‘Strongly disagree’) to 7 (‘Strongly agree’), the scale being tagged at each end with an explanatory phrase. Respondents answered questions, in an interview, and indicated the appropriate number on the Likert scale which expresses the strength of their response to the item. To avoid a fixed response set, some items are positively worded (e.g. ‘My concentration is as good as it ever was’) and others negatively (e.g. ‘I may not recover completely’). The seven positively worded items were reverse coded for aggregation and statistical analysis.
Data were analysed using the commercially available software Mokken Scaling Analysis for Polytomous items (MSP) for Windows version 5.0  and the MSA feature in the public domain software R . Data were converted from SPSS into the formats required for each of these programs and the MSP was used to identify unidimensional hierarchies of items which were subsequently analysed of IIO using the MSA in R (the statistical programme R). Using MSP the data were run using Loevinger’s coefficients from H=0.05 in 0.05 increments to H=0.45 to test for multidimensionality ; only one dimension was identified and this was subsequently run using the default settings of p<0.05 and H=0.30.
Mokken scaling of the Cardiac Depression Scale (n=603)
Dying is the best solution for me
There is only misery in the future for me
Things which I regret about my life are bothering me
I feel in good spirits*
I feel independent and in control of my life*
I get pleasure from life at present*
My memory is as good as it always was*
My concentration is as good as it ever was*
My mind is as fast and alert as always*
I gain as much pleasure from my leisure activities as I used to*
I feel like I’m living on borrowed time
I lose my temper more easily nowadays
I get hardly anything done
I can’t be bothered doing anything much
I have dropped many of my interests and activities
I seem to get more easily irritated by others than before
I feel frustrated
I may not recover completely
I am not the person I used to be
My problems are not over yet
Depression in patients with HF is associated with increased hospitalisations, decreased medication adherence, poorer health outcomes, increased mortality, and significant economic costs [5–13]. The high prevalence of depression in patients with HF  and the AHA advisory to screen for depression  indicates the need for a valid and reliable instrument. We provide evidence that the CDS is an appropriate prognostic indicator for identifying depression in patients with HF.
Although most parameters in biological systems are continuous variables, for pragmatic purposes we also heuristically organise information into identifiable groups. Thus, whilst symptoms of depressed mood and the components of diagnosed “depression’ are actually continuous variables, the diagnosis of “depression” has a dichotomous meaning that is useful for both management and determining prognosis. Whilst the CDS was originally developed to measure the full range of depressive symptoms in cardiac patients, it also has excellent accuracy for the “diagnosis” of major depression as a clinical entity (26). Nevertheless this current study was designed to examine the utility of the CDS over the full range of depressive symptoms, with the finding of a gradation from easily endorsed items through to those items representing more severe depression.
The application of Mokken scaling to the CDS has demonstrated the existence of a hierarchy of items which can be interpreted in terms of the increasingly serious effects of depression occurring as a result of a HF. Unresolved problems, frustration and irritability are at one end of the hierarchy, whilst guilt, misery and wanting to die (measures of severe depression) are at the other. The demonstration of this hierarchy provides new information (a non-parametric measure of IRT) about the structure of the CDS and adds utility to the scale in clinical practice when managing patients with HF.
Establishing unidimensional sets of items per se in assessment instruments is useful in demonstrating underlying dimensions and determining which items are related to those dimensions. The CDS, being derived from the responses of cardiac patients themselves, provides a distinctive base from which to assess item hierarchy based on the level of difficulty of items for patients with HF. However, hierarchies of items add further value: they are inherently useful because scores calculated from such sets of items help to discriminate between people better than scores from sets of items where no such hierarchy exists. A score on a hierarchical set of items indicates better the level of the latent trait because a score is related to a specific set of items, thereby providing descriptors to the level of the latent trait present. Without demonstrating that such hierarchies exist—and some sets of items are resistant to this—it is impossible to tell, for example, if two people with the same score on the instrument are both at the same level on the latent trait. If the items are not hierarchical then any set of items could contribute to any particular score and in instruments such as the CDS, these items will represent different levels of severity.
Invariant item ordering was not demonstrated for the items retained in the Mokken scale of the CDS; this means that there is no guarantee that all (HF) respondents to the CDS will respond to the hierarchy of items in precisely the same order. This could be partly explained as, within each patient cohort, there are patients who have pre-existing chronic depression as well as those with a more acute 'adjustment disorder" who might respond more strongly to a slightly different range of items. Also the lack of IIO indicates that the conceptual distance between the items is likely to be small and that there is some overlap of the item response functions because of cohesion in the scale items. Nevertheless, the Mokken scale is still useful for ordering respondents on the basis of their mean scores.
In conclusion, we found the CDS, developed as a valid and reliable cardiac-specific measure for depression, to contain a set of items that when applied to patients with HF are hierarchical. The CDS is an appropriate depression screening instrument for patients with HF that allows for early identification and better management, especially of those at increased risk of functional limitations, mortality, and impaired quality of life.
- Bui AL, Horwich TB, Fonarrow GC: Epidemiology and risk profile of heart failure. Nat Rev Cardiol 2011, 8:30–41.PubMedView ArticlePubMed Central
- Biermann J, Neumann T, Angermann CE, Erbel R, Maisch B, Pittrow D, Regitz-Zagrosek V, Scheffold T, Wachter R, Gelbrich G, Wasem J, Neumann A: Economic burden of patients with various etiologies of chronic systolic heart failure analysed by resource use and costs. Int J Cardiol 2012, 156:323–325.PubMedView Article
- Braunschweig F, Cowie MR, Auricchio A: What are the costs of heart failure? Europace 2011, 13:ii13-ii17.PubMedView Article
- Lloyd-Jones D, Adams RJ, Brown TM, Carnethon M, Dai S, De Simone G, Ferguson TB, Ford E, Furie K, Gillespie C, Go A, Greenlund K, Haase N, Hailpern S, Ho PM, Howard V, Kissela B, Kittner S, Lackland D, Lisabeth L, Marelli A, McDermott MM, Meigs J, Mozaffarian D, Mussolino M, Nichol G, Roger VL, Rosamond W, Sacco R, Sorlie P: Heart disease and stroke statistics - 2010 update: a report from the American Heart Association. Circulation 2010, 121:e46-e215.PubMedView Article
- Sherwood A, Blumenthal JA, Hinderliter AL, Koch GG, Adams KF Jr, Dupree CS, Bensimhon DR, Johnson KS, Trivedi R, Bowers M, Christenson RH, O’Connor CM: Worsening depressive symptoms are associated with adverse clinical outcomes in patients with heart failure. J Am Coll Cardiol 2011, 57:418–423.PubMedView ArticlePubMed Central
- Rutledge T, Reis VA, Linke SE, Greenberg BH, Mills PJ: Depression in heart failure: a meta-analytic review of prevalence, intervention effects, and associations with clinical outcomes. J Am Coll Cardiol 2006, 48:1527–1537.PubMedView Article
- Johnson TJ, Basu S, Pisani BA, Avery EF, Mendez JC, Calvin JE, Powell LH: Depression predicts repeated heart failure hospitalizations. J Cardiac Fail 2012, 18:246–252.View Article
- Jiang W, Alexander J, Christopher E, Kuchibhatla M, Gaulden L, Cuffe MS, Blazing MA, Davenport C, Califf RM, Krishnan RR, O’Connor CM: Relationship of depression to increased mortality and rehospitalisation in patients with congestive heart failure. Arch Intern Med 2001, 161:1849–1856.PubMedView Article
- Shimizu Y, Yamada S, Miyake F, Izumi T: The effects of depression on the course of functional limitations in patients with chronic heart failure. J Cardiac Fail 2011, 17:503–510.View Article
- Rumsfeld JS, Havranek E, Masoudi FA, Peterson ED, Jones P, Tooley JF, Krumholz HM, Spertus JA: Cardiovascular Outcomes Research Consortium. Depressive symptoms are the strongest predictors of short-term declines in health status in patients with heart failure. J Am Coll Cardiol 2003, 42:1811–1817.PubMedView Article
- Rollman BL, Helbeck Belnap BH, Mazumdar S, Houck PR, HE F, Alvarez RJ, Schulberg HC, Reynolds CF 3rd, McNamara DM: A positive 2-Item Patient Health Questionnaire depression screen among hospitalized heart failure patients is associated with elevated 12-month mortality. J Cardiac Fail 2012, 18:238–245.View Article
- Macchia A, Monte S, Pellegrini F, Romero M, D’Ettorre A, Tavazzi L, Tognoni G, Maggioni AP: Depression worsens outcomes in elderly patients with heart failure: An analysis of 48,117 patients in a community setting. Eur J Heart Fail 2008, 10:714–721.PubMedView Article
- Hallas CN, Wray J, Andreou P, Banner N: Depression and perceptions about heart failure predict quality of life in patients with advanced heart failure. Heart Lung 2011, 40:111–121.PubMedView Article
- Lichtman JH, Bigger JT, Blumenthal JA, Frasure-Smith N, Kaufmann PG, Lespérance F, Mark DB, Sheps DS, Taylor CB, Froelicher ES, American Heart Association Prevention Committee of the Council on Cardiovascular Nursing; American Heart Association Council on Clinical Cardiology; American Heart Association Council on Epidemiology and Prevention; American Heart Association Interdisciplinary Council on Quality of Care and Outcomes Research; American Psychiatric Association: Depression and coronary heart disease: recommendations for screening, referral, and treatment. A science advisory from the American Heart Association Prevention Committee of the Council on Cardiovascular Nursing, Council on Clinical Cardiology, Council on Epidemiology and Prevention, and Interdisciplinary Council on Quality of Care and Outcomes Research. Circulation 2008, 118:1768–1775.PubMedView Article
- Celano CM, Huffman JC: Depression and cardiac disease: a review. Cardiol Rev 2011, 19:130–142.PubMedView Article
- Donohue JM, Pincus HA: Reducing the societal burden of depression: a review of economic costs, quality of care and effects of treatment. PharmacoEconomics 2007, 25:7–24.PubMedView Article
- Richards D: Prevalence and clinical course of depression: a review. Clin Psychol Rev 2011, 31:1117–1125.PubMedView Article
- Swoden GL, Huffman JC: The impact of mental illness on cardiac outcomes: a review for the cardiologist. Int J Cardiol 2009, 132:30–37.View Article
- Whooley MA: To screen or not to screen? Depression in patients with cardiovascular disease. J Am Coll Cardiol 2009, 54:891–893.PubMedView Article
- Thombs BD, de Jonge P, Coyne JC, Whooley MA, Frasure-Smith N, Mitchell AJ, Zuidersma M, Eze-Nliam C, Lima BB, Smith CG, Soderlund K, Ziegelstein RC: Depression screening and patient outcomes in cardiovascular care. JAMA 2008, 300:2161–2171.PubMedView Article
- Ziegelstein RC, Thombs BD, Coyne JC, de Jonge P: Routine screening for depression in patients with coronary heart disease. J Am Coll Cardiol 2009, 54:886–890.PubMedView ArticlePubMed Central
- Holmes SD: American Heart Association guidelines for depression in screening in heart disease: call to action for the research community? J Psychosom Res 2011, 71:1–2.PubMedView Article
- Hasnain M, Vieweg WVR, Lesnefsky EJ, Pandurangi AK: Depression screening in patients with coronary heart disease: a critical evaluation of the AHA guidelines. J Psychosom Res 2011, 71:6–12.PubMedView Article
- Hare DL, Davis CL: Cardiac depression scale: validation of a new depression scale for cardiac patients. J Psychosom Res 1996, 40:379–386.PubMedView Article
- Hare DL: Imipramine in patients with chest pain despite normal coronary angiograms. N Engl J Med 1994, 330:882.
- Shi WY, Stewart AG, Hare DL: Major depression in cardiac patients is accurately assessed using the Cardiac Depression Scale. Psychother Psychosom 2010, 79:391–392.PubMedView Article
- Birks Y, Roebuck A, Thompson DR: A validation study of the Cardiac Depression Scale (CDS) in a UK population. Br J Health Psychol 2004, 9:15–24.PubMedView Article
- Di Benedetto M, Lindner H, Hare DL, Kent S: Depression following acute coronary syndromes: a comparison between the Cardiac Depression Scale and the Beck Depression Inventory II. J Psychosom Res 2006, 60:13–20.PubMedView Article
- Wise FM, Harris DW, Carter LM: Validation of the Cardiac Depression Scale in a cardiac rehabilitation population. J Psychosom Res 2006, 60:177–183.PubMedView Article
- Hemker BT, Sijtsma K: Selection of unidimensional scales from a multidimensional item bank in the polytmous Mokken IRT model. App Psychol Meas 1995, 19:337–352.View Article
- Sijtsma K, Molenaar IW: An introduction to nonparametric item response theory. Thousand Oaks, CA: Sage; 2002.
- Sijtsma K, Meijer RR, van der Ark L: Mokken scale analysis as time goes by: an update for scaling practitioners. Pers Ind Diff 2011, 50:31–37.View Article
- Sijtsma K, Junker BW: A survey of theory and methods of invariant item ordering. Brit J Math Stat Psychol 1996, 49:79–105.View Article
- Stewart ME, Watson R, Clark A, Ebmeier KP, Deary IJ: A hierarchy of happiness? Mokken scaling analysis of the Oxford Happiness Inventory. Pers Ind Diff 2010, 48:845–848.View Article
- Watson R, Deary I, Austin E: Are personality trait items reliably more or less ‘difficult’? Mokken scaling of the NEO-FFI. Pers Ind Diff 2007, 43:1460–1469.View Article
- Watson R, Deary IJ, Shipley B: A hierarchy of distress: Mokken scaling of the GHQ-30. Psychol Med 2008, 28:575–579.
- Watson R, Wang W, Hare DL, Ski CF, Thompson DR: The Chinese version of the Cardiac Depression Scale: Mokken scaling. Health Qual Life Outcomes 2012, 10:1–4.View Article
- Watson R, Wang W, Ski CF, Thompson DR: The Chinese version of the Myocardial Infarction Dimensional Scale: Mokken scaling. Health Qual Life Outcomes 2012, 10:2–4.PubMedView ArticlePubMed Central
- Molenaar IW, Sijtsma K: Users manual MSP5 for Windows: a program for Mokken scale analysis for polytomous items. Groningen: iec ProGAMMA; 2000.
- van der Ark LA: Mokken scale analysis in R. J Stat Soft 2007, 20:1–19.
- Meijer RR, Baneke JJ: Analyzing psychopathology items: a case for nonparametric item response theory modelling. Psychol Methods 2001, 9:354–368.View Article
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.