From the Editor

How do we improve mental health services?

Past Readings have explored many topics from measurement-based care to better access. This week, we consider a new paper by Aalborg University’s Line Ryberg Rasmussen et al. The study authors look at volume and quality of mental health care, drawing on Danish inpatient admissions.

Their finding? “This nationwide, population-based cohort study demonstrated that patients with depression who were admitted to psychiatric hospitals with very-high-volume wards were more likely to receive care in accordance with clinical guidelines, compared with those admitted to low-volume wards.”

ptelemnursing01High volume, better care (if not better cafeteria food)?

This week, we look at the Rasmussen et al. paper and consider its implications.



“Inpatient Volume and Quality of Mental Health Care Among Patients With Unipolar Depression”

Line Ryberg Rasmussen, Jan Mainz, Mette Jørgensen, Poul Videbech, Søren Paaske Johnsen

Psychiatric Services, 26 April 2018 PS In Advance

There is a growing interest in the association between inpatient volume and the quality of care, and the organizational structure in the health care sector, such as inpatient volume in hospital units, is a topic of discussion worldwide. The objective of the discussion is to ensure better treatment quality, higher patient satisfaction, and more efficiency. Several observational studies have examined the association between inpatient volume and clinical outcomes for surgical procedures and various medical conditions. The evidence from these studies indicates that higher inpatient volume is associated with better clinical outcomes, including reduced complications and lower mortality. Despite the increasing interest, an analogous association between inpatient volume and the quality of mental health care has not been examined properly.

To our knowledge, only six published studies have examined this association. However, the results of these studies are inconsistent, making it difficult to draw conclusions. Furthermore, only one of the existing studies has examined the association specifically for patients with depression, and there is a general lack of studies with detailed data regarding the quality of the provided mental health care. To further assess the role of inpatient volume in mental health care, we conducted a nationwide population-based cohort study to examine the association between inpatient volume per psychiatric hospital ward and the quality of mental health care, as reflected by the receipt of specific guideline-based processes of care among Danish patients admitted with depression.

0Line Ryberg Rasmussen

So begins a paper by Rasmussen et al.

Here’s what they did:

  • The authors drew data from the Danish Depression Database, which contains information on all inpatient hospitalizations in Denmark.
  • The study included all patients 18 and older, with a primary diagnosis of depression, between 1 January 2011 and 31 December 2016. Hospital wards with fewer than 20 admissions during the study period were excluded.
  • Inpatient volumes were divided into “low volume (quartile 1, <102 inpatients per year), medium volume (quartile 2, 102–172 inpatients per year), high volume (quartile 3, 173–227 inpatients per year), and very high volume (quartile 4, >227 inpatients per year).”
  • Quality of care was measured using several performance measures, which were based on depression guidelines: examination by a psychiatrist, somatic examination, assessment by a social worker, assessment of depression (soon after admission and upon discharge), assessment of suicide risk (upon admission and before discharge), contact with relatives, and plans for psychiatric aftercare. Quality of care was determined by the number of these performance measures completed during an admission. Statistical analyses were done.

Here’s what they found:

  • There were 17,971 patients with 21,120 admissions during the study period.
  • Demographically: “Characteristics of patients in the four quartiles of inpatient volume did not vary substantially.” Patients tended to be older (over 60) and female.
  • “The proportion of patients receiving ≥80% of the recommended process performance measures varied between 11.8% and 21.0%.” See table 2 below.
  • “Patients admitted to very-high-volume psychiatric hospital wards had a higher likelihood of receiving high overall quality of care (≥80% of the process performance measures), compared with patients admitted to low-volume wards…”
  • In terms of statistical analysis: “Patients admitted to very-high-volume wards had a higher likelihood of being somatically examined, compared with those admitted to low-volume wards (ARR=1.35…). In addition, a multinomial logistic regression demonstrated that admission to very-high-volume wards was associated most strongly with the highest level of quality of care (>90% of the process performance measures). Hence, admission to a very-high-volume ward was associated with an adjusted RR of 1.11 for receiving >50%−70% of the process performance measures, whereas the adjusted RR for receiving >90% of the process performance measures was 2.39…”


Our results showed a small but statistical significant association between inpatient volume and quality of mental health care among patients with depression. Patients with depression who were admitted to very-high-volume wards were more likely than those admitted to low-volume wards to receive 80% or more of process performance measures, including a somatic examination. However, no significant association with quality of mental health care was found with a continuous increase in inpatient volume. The differences in care between hospitals above the lowest patient volume category were small or nonexisting, and the findings may therefore imply that low-volume psychiatric hospital wards are challenged with delivering optimal care for inpatients with depression—at least in some areas of care.

A few thoughts:

  1. This is a good study.
  1. Higher volume = better care. Why? The authors put forward several explanations. “Underlying mechanisms in high-volume psychiatric hospital wards, such as specialization, greater clinical experience, and better resources, might explain the observed association between psychiatric hospital wards with very high volume and the highest overall quality of care for patients with depression. Furthermore, a greater number of beds and shorter stays may characterize high-volume psychiatric hospital wards.” The result is in keeping with the other big paper in this field, which was published in The American Journal of Psychiatry in 2004 (which can be found here:
  1. These explanations seem right. They also are not specific to mental health. And with that, another comment: it’s striking how reproducible that result is across health care. The connection between surgical outcomes and volume has been studied for decades. (See, for example, this landmark New England Journal of Medicine paper:
  1. In the study, quality of care was heterogeneous. “Only 35% to 44% of admitted patients are seen by a psychiatrist within seven days, and only about one-half of the patients received a suicide risk assessment at admission and discharge. Likewise only about 40% had planned psychiatric aftercare.”
  1. The measure of quality care was reasonable – but not ideal. The study didn’t consider, as an example, outcomes (like patient depression scores decreasing over admissions).
  1. It should be noted that the paper drew from a database, allowing for a large sample size. As is the case with such studies, confounding factors need to be considered.
  1. There is a larger public-policy point here. As funding for mental health care increases, the temptation to branch out in many directions is great. But quality care depends partly on volume, and spending would be more effective if it would more focused rather than diffuse.


Reading of the Week. Every week I pick articles and papers from the world of Psychiatry.