The finding:
This large-scale population-based cohort study of Canadian patients aged ≥ 66 years found that that lithium was associated with a 14% increased risk of clinically important decrease in renal function (30% or greater decrease in eGFR from baseline) compared to valproate users, over an average follow-up of about three years. In addition, higher lithium levels (> 0.7 mmol/L) may be associated with subsequent risk of renal decline (HR 1.26) which was not observed with lower levels.

Strength and weaknesses:

Strengths-
This is the first large study to examine the effects of serum lithium levels on renal outcomes. The study was five times larger and focused on geriatric patients which permitted mitigation of various confounding factors. Valproate users were chosen as a control to reduce confounding by indication and relevant physical comorbidities. Despite the use of a propensity score, there may be residual confounding. Secondary analysis (lithium levels and renal decline) may have been underpowered.

Relevance:
There appears to be a substantial association between lithium use and clinically important decrease in renal function, however, the association appears smaller than previously reported.  The study suggests that lower levels (≤ 0.7 mmol/L) may be helpful at mitigating the risk of lithium renal toxicity. This is consistent with expert consensus guidelines that recommend lower lithium levels (0.4–0.8 mmol/L for ages 60–79 and levels 0.4–0.7 mmol/L for ages ≥ 80 to minimize toxicity, while having clinical effectiveness in older age bipolar disorder and late-life depression). Other studies have also shown psychiatric stability and neuroprotective effects with lithium are likely observed at < 0.7 mmol/L for most older adults.  The study reinforces the need for increased monitoring of lithium levels and eGFR in older adults. Clinicians should screen older patients for lithium levels and renal function every 3 months consistent with NICE and ISBD guidelines.

Type of study (EBM guide):
Cohort study

The finding:
This is the first study to examine the risks involved with starting lithium treatment in patients with baseline renal impairment. Half of the exposed cohort on lithium (progressors) vs 10% reference patients progressed to severe renal impairment (HR 6.7). These progressors were significantly older and had a higher burden of somatic comorbidity. They also found previous lithium exposure might increase the risk of developing CKD 4–5 in patients with elevated s-creatinine when they are exposed to lithium treatment anew.

Strength and weaknesses:
The study tried to limit confounding factors by matching the groups by gender, age, and duration of lithium treatment. The study encompasses a long observation time and good characterization of the patient cohorts. However, the study was conducted in only one Swedish hospital. Severity and timeline of comorbid conditions could not be graded. Review of the medical charts was only performed for the exposed cohort which may have introduced a bias in comparing both groups. Results may not be generalizable to younger patients given the mean age of over 60 years old in the study.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           

Relevance:
The study highlights an increased risk of developing severe renal impairment in patients with compromised renal function prior to initiating lithium. C-L psychiatrists should be mindful of initiating lithium in these patients, especially if they are older with significant comorbidity; the risk of severe renal impairment should be weighed against the well-known benefits of preventing the recurrence of mood episodes and reduction in suicide risk. It should also be noted that half the patients in the study with elevated s-creatinine at the start of lithium treatment did not develop severe renal impairment. Therefore, clinicians may choose not to withhold prophylactic treatment with lithium especially if there is a strong indication in these patients with close monitoring.

Type of study (EBM guide):
Cohort study

The finding:
This case-control study evaluated the association of developing chronic kidney disease and second-generation antipsychotics. Participants included a large database in Denmark, separating patients with kidney disease and those without. The risk of chronic kidney disease was elevated in patients who had previously or were currently taking second-generation antipsychotics for either short or long duration. The highest risk of chronic kidney disease was found in those patients prescribed clozapine.

Strength and weaknesses:
One of the strengths of the studies was the population approach and the availability of data amongst all inhabitants on an island in Denmark over a four-year period. Another strength was controlling for some factors, including hypertension, prior lithium use,
 and non-steroid anti-inflammatory drugs. The study failed to describe other confounders. For example, although there was an increased risk of kidney disease with second-generation antipsychotics, lifestyle and behaviours in patients prescribed antipsychotics, or metabolic effects of second-generation antipsychotics may also predispose patients to kidney injury.

Relevance:
This article is relevant to the field of consultation-liaison psychiatry as second-generation antipsychotics are widely prescribed and can contribute to further medical complications that need to be closely monitored and managed.

Type of study (EBM guide):
Case control study

The finding:
Given the recent stressors that healthcare workers are enduring, this study aimed to evaluate the stigma and stress among dialysis staff. Although healthcare workers have been praised for their ongoing dedication to patients, many have been shunned based on their exposure levels. By May 2020, there had been over 200 attacks on healthcare works secondary to the pandemic, which also included active denial on public transportation and housing facilities. This study sent a survey to dialysis staff regarding the level of stigma they had experienced due to the pandemic. Of the 335 gathered responses, over half of the dialysis staff had experienced perceived stigma.

Strength and weaknesses:
The strength of the study was to expose how stigma in healthcare workers has increased as a result of the pandemic, specifically amongst dialysis staff. One weakness is that the study did not compare levels of stigma between healthcare and non-healthcare workers.

Relevance:
This article is relevant to the field of consultation-liaison psychiatry as we need to develop better avenues to manage the stigma within the healthcare system, and thus better address the stress that healthcare workers are experiencing as a result of the pandemic.

Type of study (EBM guide):
Cohort study