Methodology

The University of Queensland Human Research Ethics Committee approved the study protocol. The WORC project has been registered with the Australian New Zealand Clinical Trials Registry (ANZCTR; www.anzctr.org.au)

The aim of the Work Outcomes Research Cost-Benefit (WORC) Project was to identify employees with untreated depression and test the hypothesis that telephone outreach and care management of employees with depression results in an increment in employee productivity. The WORC project has several distinct phases. Phase one is the recruitment of large Australian employers to participate in the project. The second phase is to recruit employees of those large employers to answer a Health survey (The World health Organisation Health and Work Performance Questionnaire [HPQ]). The HPQ is designed to monitor the prevalence of acute and chronic physical and mental health conditions, and evaluate risk factors for illness, enabling employers to target intervention ^1-4. Further information on the HPQ can be located at http://www.hcp.med.harvard.edu/hpq/.

Embedded in the HPQ is the Kessler 6 (K6). The K6 is a psychological distress scale which can be used to assess mental health symptom severity ^5-8. The third phase of the project was to further screen subjects positive for psychological distress on the K6 for more specific depression symptoms. This screen was by the telephone where call operators asked the Quick Inventory of Depressive Symptomatology (QIDS) survey, the Patient Health Questionnaire 9 (PHQ 9) ⁹, the Composite International Diagnostic Interview short form screening questions for mania or substance dependence ¹⁰ and questions regarding treatment for mental health conditions.

Employees that screened positive of the QIDS and the PHQ for depression symptoms and who were not in treatment and did not meet criteria for substance misuse or mania and who consented for further contact were eligible for further participation in the WORC project. These employees were followed up by a phone call from a psychologist and received the single contact (SC) procedure. During this phone call participants were informed that they might be experiencing symptoms of depression and were advised to access assessment / treatment in their local area. Barriers to treatment were assessed and addressed by the psychologist using psycho-education, cognitive behavioural and motivational interviewing techniques. In addition, the psychologist provided information regarding treatment options, an individualised referral for in-person assessment and treatment letter for a GP and consent forms, written information and resources using a standard pack of information.

Following the SC depression participants were randomised into either the SC or care managed treatment groups. Participants randomised into single contact received no further contact from the study psychologists. Participants in the Care Managed group received ongoing contact with a psychologist over the course of the next 12-months. Contents of these contacts are described below in the care management section.

In addition to the two depression treatment groups a group of non-depressed employees was also recruited as a control population. A 2% random sample of employees that scored negative on the K6 were asked the QIDS. Those negative for depression on the QIDS were recruited for participation.

Outcome measures for the three groups (Controls, Single Contact and Care Managed) were symptoms as measured by the QIDS, absenteeism and presenteeism as measured in the HPQ. At 6-weeks, 3-months, 6-months and 12-months post the initial contact with a psychologist a call operator administered a telephone version of the QIDS and the HPQ. Care management concluded at the 12-month mark. To see if any productivity and symptomatic changes were maintained The QIDS and HPQ were asked at 18-months post the first contact being 6-months after the conclusion of the Care Management program.

Recruitment of Employers

Two hundred and one large government and private sector employers across Australia were contacted and invited to participate in the Work Outcomes Research Cost-Benefit (WORC) Project. The project was presented to employers as a proactive health screening and treatment facilitation program for depression in the workplace. Employers were advised that the focus of the research was to establish the economic return on investment, from the employer’s perspective, of detecting undiagnosed depression in the workplace and facilitating treatment of these employees.

Initial contact with prospective companies was normally through the OH&S officer or, less frequently, the HR manager. The duration of the consultative process varied from 3-months to 12-months and typically extended from the OH&S Officer or HR to senior management, IT personnel, CEO, communications advisor, and where relevant, an ethics committee or legal personnel. The initial contact with organisations was generally via the phone and was followed by an emailed written description of the Project. Organisations were characteristically followed up with a telephone call within two to three weeks to further discuss the proposal and where possible arrange a face-to-face meeting.

Organisations were advised that participation in the project would incur no direct cost, that is, no cash contribution. For the employer, the cost involved (1) a representative of the organization working with the researchers to coordinate the promotion and implementation of the survey within the organisation and (2) employees time to complete the survey (approximately 20 minutes per employee). In the initial correspondence period, organisations were provided with information about depression, its prevalence, under diagnosis and under treatment, and estimates of the costs of depression in relation to work performance and productivity. Employers were additionally advised that expected outcomes from involvement in the screening project included an increase in employee health and well-being, increased employee productivity, decreased absenteeism, decreased employee turnover, decreased disability claims, and decreased job related accidents. Employers were informed that the WORC project would supply them with a report on the general (physical and mental) health status of the organisation’s employees , and would outline the prevalence of a variety of disorders as measured in the WORC Project using the HPQ, benchmarked against national prevalence figures. Organisations were advised that at the completion of the research period they would be presented with a summary of the findings on the mental health status of employees, including a financial cost-benefit analysis in terms of how much it cost to run the WORC Project and how much was gained in monetary terms from increased employee productivity.

A database was maintained of all correspondence, discussions, meetings, e-mails and outcomes, including stated reasons for non-participation for each invited employer.

Of the 201 employers invited to participate in the WORC project, 68 declined participation, 69 failed to make a decision by the required date. Six organisations were ruled out after approach, as they did not meet eligibility criteria (> 1,000 employees). Fifty-eight employers agreed to participate in the WORC Project. Fifty-two of the 69 declining organisations provided a reason for not participating in the project.

Recruitment of employees

HPQ surveys were circulated to employees of the participating organisations using either paper-based or web-based methods depending on company-specific logistical considerations. Each survey was accompanied by a letter stating that the survey was a general health and emotional well-being survey. To emphasise only the mental health component would have altered response rates, particularly in men ^11,12. Employees were encouraged to answer surveys by at least two reminders in the one-month survey period for each company. Only employees over the age of 18-years were invited to participate. Participation in the survey was voluntary and confidential. At the end of the survey was a consent section where respondents indicated their willingness to be further contacted about their survey results.

Approximately 445,583 employees were invited to complete the HPQ between October 2004 and October 2005. 90,279 HPQ surveys were received between October 2004 and December 2005. Data cleaning yielded 78,726 records eligible for further analysis. 60,556 HPQ records were from full-time employees, 15,521 were from pert-time employees and 2,398 from casual employees. 251 records did not indicate whether the employee was full-time, part-time or casual.

Screening for depression using the QIDS

Only full-time employees from the HPQ described above were eligible for further contact.

The HPQ contains a non-specific scale of psychological distress the Kessler 6 (K6). The K6 strongly discriminates between community mental health cases and non-cases ^5-8. Employees with possible depression (K6 score ≥ 9; N = 10,665) and who consented for further contact on the HPQ were considered eligible for further contact (N = 2,769). In addition a 2% random sample of employees with K6 < 9 was recruited as possible healthy (non-depressed) control subjects (N = 749). Potential depressed and control subjects were contacted by a call centre operator who verbally consented the subjects and if consent was obtained they administered the Quick Inventory of Depression Symptoms Self Report (QIDS-SR) ¹³, the Patient Health Questionnaire 9 (PHQ 9) ⁹, the Composite International Diagnostic Interview short form screening questions for mania or substance dependence ¹⁰ and questions regarding treatment for mental health conditions. 2,381 of the potentially depressed population were contactable by the telephone call centre for the baseline QIDS evaluation. 654 control subjects were contactable for baseline QIDS evaluation.

Two stem questions from the QIDS-SR determined eligibility for the study. The first was question IDS 5 is, during the past seven days how often did you feel sad? The second question was IDS 11, during the past seven days, how much of the time did you lose interest or enjoyment in people or activities that used to interest you or which you used to enjoy. To be eligible for the depression group respondents were required to respond with at least “less that half the time” for either or both QIDS-SR stem questions. In addition, to be eligible for the depression group respondents required a PHQ score of ≥ 5. Thus in total to be eligible for the depression group respondents must have had a K6 ≥ 9, positive on questions QIDS-SR 5 and 11 and have a PHQ score ≥ 5. Exclusions for eligibility into the depressed group were positive for mania or substance dependence or in current treatment for a mental health condition where current treatment is defined as taking psychoactive medication or two or more visits to a qualified mental health professional in the past month; or at least monthly visits to a qualified mental health professional in the past 6 months. To be eligible as a control subject respondents must have had a K6 ≤ 9, negative on QIDS-SR questions 5 and 11 and a PHQ score < 5. Following the baseline QIDS, 901 potentially depressed subjects and 373 control subjects remained eligible and consented to further participation in the study protocol. Subsequently 56 control subject failed to return written consent forms and 2 withdrew from the protocol leaving 315 control subjects completing the study.

Single Contact

All eligible consenting depression participants were followed up by a phone call from a psychologist and received the single contact (SC) procedure. Of the 901 potentially depressed subjects for contact by study psychologists 38 subjects were not contactable leaving 863 that were contacted by psychologists. Of the 863 contacted, 18 were deemed ineligible (primarily due to being in current treatment) and 224 refused consent for further participation in the protocol leaving a pool of 621 depressed subjects. During the single contact phone call participants were informed that they might be experiencing symptoms of depression and were advised to access assessment / treatment in their local area. Barriers to treatment were assessed and addressed by the psychologist using psycho-education, cognitive behavioural and motivational interviewing techniques. In addition, the psychologist provided information regarding treatment options, an individualised referral for in-person assessment and treatment letter for a GP and consent forms, written information and resources using a standard pack of information.

Randomisation

Following the single contact depression participants were randomised, using a random number generator, into either the single contact (N = 275) or care managed (N = 346) treatment groups. Participants randomised into single contact received no further contact from the study psychologists. Due to logistical consideration there was a substantial delay (> 1-month) in contacting 52 participants in the care manager group. It was decided to reassign these subjects into the single contact condition thus this yielded 294 Care Manager subjects and 327 single contact subjects. During the course of the 18-month protocol 50 Care Manager subjects and 46 single contact subjects withdrew their consent for study participation. This left 244 Care Manager subjects and 281 single contact subjects eligible for final analysis.

Care Management Program

The semi-structured care manager telephone intervention programme provided systematic assessment on each contact, need for treatment, facilitated entry into in-person treatment (pharmacotherapy and psychotherapy), monitored and supported treatment adherence, addressed barriers to treatment seeking and adherence and provided structured CBT for those unable to access or declining in-person treatment. Care manager psychologists were a mix of doctorate level psychology postgraduates and registered psychologists. Additional training for the study was provided along with group and individual supervision for approximately 120 minutes a week (from Dr. J.S. and Dr. D.H.) throughout the study and had approximately 45 individuals in their case loads. A consultant psychiatrist was available for consultation (Prof. H.W.).

The initial telephone contacts included assessment of depressive symptoms PHQ-9, prior treatment, psycho-social stressors and complicating issues (addictive behaviours / domestic violence / PTSD), and barriers to treatment. For all participants with significant depressive symptoms care managers recommended seeking in-person assessment / treatment from their general medical practitioner (GP) and psychotherapy, provided referral information and letters to GPs to assist the person in accessing treatment. Subsequent contacts by the care managers for participants who entered in-person treatment included structured assessment of depressive symptoms, discussion about treatment, any difficulties the person might be experiencing, assessment of medication side-effects, and complicating factors that might impact on treatment adherence.

Session duration for participants in treatment was approximately 30 to 45 minutes. The average number of contacts made with each participant was 8.5. Those participants who were physically / geographically unable to access in-person treatment and those participants who remained opposed to in-person treatment were offered a CBT programme with sessional notes, homework and information sheets with follow-up sessions to consolidate skills and develop self-help / care plans. All participants continued to receive monitoring and booster sessions every 4-6 weeks up to 12-months from initial contact. Care management procedures were supported by an electronic administered database and programme. Care manager procedures and therapist manual is available on request. All care manager and SC interventions were provided without charge to the employee. However, employees that sought treatment as a result of the intervention had to pay for their own treatment as per standard means.

Outcome measures

QIDS

The QIDS-SR used in this study was adapted for telephone administration. It is a brief self-report measure that reflects symptom severity, as well as being sensitive to symptomatic change ¹⁴. The QIDS-SR correlates significantly, with the 17-item Hamilton Rating Scale for Depression (HRSD) ¹⁵. It is intended as a short diagnostic interview, comprising of the nine domains of DSM-IV criteria. Thresholds recommended to estimate depression severity are mild (6-10), moderate (11-15), severe (16-20) and very severe (>20) ¹³.

Health and Work Performance Questionnaire (HPQ)

The World Health Organisation Health HPQ was chosen as it is a widely applied and validated employee questionnaire designed to assess the impact of acute and chronic health conditions on employee productivity (absenteeism and presenteeism). The HPQ collects self-reported absenteeism and presenteeism in the past 28-days. Although self report is associated with inherent error, blinded evaluations report strong associations (r = 0.61 to 0.87) of HPQ absenteeism to objective payroll records ¹. HPQ presenteeism measures correlate well with supervisor ratings and other administrative indicators of performance ^1,4.

Absenteeism

To quantify absenteeism the HPQ asks a number of questions about hours missed from work. The first question probes employees about the hours they actually worked in the past seven-days. The second question asks employees to report how many hours their employer expects them to work in a typical seven-day period. Similar to previously reported absenteeism ratio methods ^16-18, absenteeism is calculated as (number of expected hours minus number of actual hours) / number of expected hours and represented as a percent. Thus, positive percentages indicate an employee is at work less than expected (absenteeism) and negative percentages reflect that an employee is at work more than expected (extensionism). Extensionism has been previously discussed ^17,18 and is defined by working longer hours than an employer expects. Using the absenteeism-extensionism continuum may more accurately reflect workplace practice than traditional recording of just days absent which does not capture extra hours or days worked to compensate for lost time or reduced performance.

Presenteeism

Several researchers have employed the method of adjusting employee’s performance by their self-report perceptions of their own productivity in relation to that of others in similar jobs ^1,19-23. A detailed explanation of the rationale and calibration studies around presenteeism is available ¹. First the HPQ asks the respondents several memory priming questions around different aspects of job performance (e.g. concentration, working carefully, quality of work). Following the memory priming questions the respondent is asked to rate the performance of an average person (P_average), working in a similar job to their own on a self-anchoring scale of performance of 0-10 (worst to best). Respondents also ranked their own performance (0–10 scale) over the past 28-days during the time they were at work (P_own). The formula used to calculate presenteeism is

Where division by 10 is the scope of the scale and multiplication by 100 converts to a percentage. Thus, positive percentages indicate an employee’s performance is less than co-workers (positive presenteeism), and negative percentages reflect that an employee is performing better than co-workers (negative presenteeism). This method bounds the data from -100% to 100%. Where 0% is an employee who is working at the same level as co-workers, -100% is an employee who rates their performance at the maximum level (10/10) and others performance at the minimum level (0/10). Similarly, 100% is a complete absence of productivity.

Productivity

Using the methods for absenteeism and presenteeism described above the total productivity (Tp) of employees was calculated by the product of absenteeism with presenteeism.

Positive productivity percentages indicate an increase in productivity (greater output than employer expects) negative percentages represent decreased productivity (lower output than employer expects).

References

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