12, 13, 19 The largest study, based on population-based SEER-data, showed that patients with LNMM had a prognosis that was in between the prognosis of node negative patients and of pN1 patients.
This is the largest study based on number of admissions with asthma admitted to adult critical care units ever undertaken (see table 1).
However, to avoid epidemiological biases, such as selection bias or chance findings, large studies based on quality-assured and comparable data sets from population-based cancer registries are preferable.
It has been widely used in large studies based on administrative data to predict functional outcome [33], implant survival [34], mortality [35], and length of hospital stay and resource use [7, 16].
According to three large studies based on thousands of subjects from UK and Denmark, it can be concluded that long-term exposure to lithium is associated with increased rates of CKD (Close et al. 2014; Kessing et al. 2015; Hayes et al. 2016).
Therefore, larger studies based on incident cases are warranted.
Two recent, large studies based on Norwegian registry data, demonstrated no clinically significant impact of hyperemesis on birth outcomes [ 4- 6].
Another tendency is the publication of large studies based upon large population samples (e.g. census), with often less information on confounding variables such as individual smoking habits.
This allowed us to consider some possible confounders, such as maternal comorbidity or personal information, not included in other large studies based on nationwide registries or large databases.
One of these reviews [ 2] included 11 RCTs (mean sample 168 patients), 18 comparative observational studies including two very large studies based on Scandinavian registry data [ 22], and 159 observational studies.
