Table 4.
Quality assessment for the included studies
| Year | Author | Sample Size | Q1 | Q2 | Q3 | Q4 | Q5 | Q6 | Q7 | Q8 | Q9 | Q10 | Q11 | Q12 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Controls | Patients | ||||||||||||||
| A. Immunoglobulins | |||||||||||||||
| 2017 | Kanchanatawan et al. | 40 | 84 clinically stable Sz outpatients | Yes | CD | NR | Yes | Yes | Yes | NR | Yes | NA | Yes | NR | Yes |
| 2018a | Kanchanatawan et al. | 40 | 80 Sz outpatients, 40 deficit, and 40 non-deficit patients | Yes | Yes | Yes | Yes | Yes | Yes | No | No | Yes | Yes | NA | Yes |
| 2018b | Kanchanatawan et al. | 40 | 80 Sz outpatients, 40 deficit, and 40 non-deficit patients | Yes | CD | Yes | Yes | Yes | Yes | NR | CD | NA | Yes | Yes | Yes |
| 2010 | Bechter et al. | 4100 | Inpatient Sz = 39, inpatient Af = 24 | Yes | Yes | No | Yes | Yes | Yes | No | No | Yes | Yes | NA | No |
| B. Interleukins | |||||||||||||||
| 2017 | Szymona et al. | 45 | 51 Sz inpatients due to acute relapse at time of admission, after a 4-week treatment and remission | Yes | Yes | NR | Yes | Yes | Yes | NR | Yes | NA | Yes | Yes | Yes |
| 2009 | Barry et al. | 36 | 34 outpatients (Sz or SzA disorder | Yes | Yes | No | Yes | Yes | Yes | No | No | Yes | Yes | NA | Yes |
| 2009 | Kim et al. | 174 | 71 acute admitted medication-naïve psychotic patients or medication-free for at least 4 months assessed on admission and discharge after 6 weeks. | Yes | Yes | NR | Yes | Yes | Yes | NR | CD | NA | Yes | Yes | Yes |
| 2015 | Schwieler et al. | 37 | 23 Sz outpatients | Yes | Yes | No | Yes | Yes | Yes | No | No | Yes | Yes | NA | Yes |
| 2017 | Kegel et al. | Outpatient (MZ) | Outpatient (DZ) | Yes | Yes | No | Yes | Yes | Yes | No | No | Yes | Yes | NA | Yes |
| 12 (2 single twins) | 11 (one single twin) | ||||||||||||||
| C. C-reactive protein | |||||||||||||||
| 2017 | Wurfel et al. | 92 | Inpatient MDD (N = 35), BD (N = 53), SzA (N = 40), acutely ill Sz (n = 21) | Yes | CD | NR | Yes | Yes | Yes | NR | CD | NA | Yes | Yes | Yes |
Abbreviations: CD cannot determine, NA not applicable, NR not reported, Af affective disorder, DZ dizygotic twins, MDD major depressive disorder, MZ monozygotic twins, Sz schizophrenia, SzA schizo-affective disorder
Questions: Q1. Was the research question or objective in this paper clearly stated? Q2. Was the study population clearly specified and defined? Q3. Was the participation rate of eligible persons at least 50%? Q4. Were all the subjects selected or recruited from the same or similar populations (including the same time period)? Were inclusion and exclusion criteria for being in the study prespecified and applied uniformly to all participants? Q5. Was a sample size justification, power description, or variance and effect estimates provided? Q6. For the analyses in this paper, were the exposure(s) of interest measured prior to the outcome(s) being measured? Q7. Was the timeframe sufficient so that one could reasonably expect to see an association between exposure and outcome if it existed? Q8. For exposures that can vary in amount or level, did the study examine different levels of the exposure as related to the outcome (e.g., categories of exposure, or exposure measured as continuous variable)? Q9. Were the exposure measures (independent variables) clearly defined, valid, reliable, and implemented consistently across all study participants? Q10. Was the exposure(s) assessed more than once over time? Q11. Were the outcome measures (dependent variables) clearly defined, valid, reliable, and implemented consistently across all study participants? Q12. Were the outcome assessors blinded to the exposure status of participants? Q13. Was loss to follow-up after baseline 20% or less? Q14. Were key potential confounding variables measured and adjusted statistically for their impact on the relationship between exposure(s) and outcome(s)?
Taken from: The National Heart, Lung and Blood Institute. Study Quality Assessment Tools. Available at: https://www.nhlbi.nih.gov/health-topics/study-quality-assessment-tools