To describe the incidence and types of spin in systematic reviews of platelet-rich plasma (PRP) injections for hip osteoarthritis (OA) and to determine whether patterns in study characteristics could be identified among studies with identifiable spin.

The PubMed, Scopus, and SPORTDiscus databases were queried. Inclusion criteria were systematic reviews or meta-analyses that included an assessment of intra-articular PRP injections as a stand-alone treatment for hip OA. Two authors independently assessed the presence of spin in the included studies and recorded general study characteristics. The prevalence of the 15 different categories of spin was quantified using descriptive statistics.

Fifteen studies met inclusion criteria for this study. All studies contained at least two types of spin (range 2-9), with a median of 2. The most common type of spin was type 14 ("Failure to report a wide confidence interval of estimates"), which was observed in 10 studies. The second most common type of spin was type 13 ("Failure to specify the direction of the effect when it favors the control intervention"), found in 6 studies.

Spin is highly prevalent in abstracts of systematic reviews of PRP in the treatment of hip OA. Several associations were found between spin types and the study characteristics of AMSTAR 2 rating, Scopus CiteScore, journal impact factor, and PROSPERO preregistration. When present, spin in the abstracts of reviewed studies tended to favor the use of PRP in hip osteoarthritis.

It is important to understand the prevalence of spin in published abstracts, especially in areas of great impact or interest, so authors and readers can have a greater awareness of this potential form of bias.

Hypoxia-inducible factor-prolyl hydroxylase domain inhibitors (HIF-PHIs) are a novel group of drugs used to treat renal anemia, but their benefits vary among different trials. Our meta-analysis aims to assess the safety and efficacy of HIF-PHI versus erythropoiesis-stimulating agents (ESA) in managing anemia among patients with chronic kidney disease (CKD), regardless of their dialysis status. PubMed, Embase, and Google Scholar were queried to discover eligible randomized controlled trials (RCTs). To quantify the specific effects of HIF-PHI, we estimated pooled mean differences (MDs) and relative risks (RR) with 95% CIs. Our meta-analysis involved 22,151 CKD patients, with 11,234 receiving HIF-PHI and 10,917 receiving ESA from 19 different RCTs. The HIF-PHI used included roxadustat, daprodustat, and vadadustat. HIF-PHI yielded a slight but significant increase in change in mean hemoglobin (Hb) levels (MD: 0.06, 95% CI (0.00, 0.11); p = 0.03), with the maximum significant increase shown in roxadustat followed by daprodustat as compared to ESA. There was a significant decrease in efficacy outcomes such as change in mean iron (MD: -1.54, 95% CI (-3.01, -0.06); p = 0.04), change in mean hepcidin (MD: -21.04, 95% CI (-28.92, -13.17); p < 0.00001), change in mean ferritin (MD: -16.45, 95% CI (-27.17,-5.73); p = 0.03) with roxadustat showing maximum efficacy followed by daprodustat. As for safety, HIF-PHI showed significantly increased incidence in safety outcomes such as diarrhea (MD: 1.3, 95% CI (1.11, 1.51); p = 0.001), adverse events leading to withdrawal (MD: 2.03, 95% CI (1.5, 2.74), p = 0.00001) among 25 various analyzed outcomes. This meta-analysis indicates that HIF-PHIs present a potentially safer and more effective alternative to ESAs, with increased Hb levels and decreased iron usage in CKD patients without significantly increasing adverse events. Therefore, in these patients, we propose HIF-PHI alongside renal anemia treatment.

Hyperphosphatemia and anemia, which are common complications of chronic kidney disease (CKD), can independently contribute to cardiovascular events. Several previous studies have found that the iron-based phosphate binder, ferric citrate (FC), could be beneficial to both hyperphosphatemia and anemia.

Relevant literature from PUBMED, EMBASE, the Cochrane Central Register of Controlled Trials (CCRCT) and MEDLINE databases were searched up to 21 February 2022, in order to conduct a meta-analysis to investigate the efficacy, safety and economic benefits of ferric citrate treatment in CKD patients with hyperphosphatemia and anemia. The meta-analysis was conducted independently by two reviewers using the RevMan software (version 5.3).

In total, this study included 16 randomized clinical trials (RCT) involving 1754 participants. The meta-analysis showed that ferric citrate could significantly reduce the serum phosphorus in CKD patients compared to the placebo control groups (MD -1.76 mg/dL, 95% CI (-2.78, -0.75); p = 0.0007). In contrast, the difference between ferric citrate treatment and active controls, such as non-iron-based phosphate binders, sevelamer, calcium carbonate, lanthanum carbonate and sodium ferrous citrate, was not statistically significant (MD - 0.09 mg/dL, 95% CI (-0.35, 0.17); p = 0.51). However, ferric citrate could effectively improve hemoglobin levels when compared to the active drug (MD 0.43 g/dL, 95% CI (0.04, 0.82); p = 0.03) and placebo groups (MD 0.39 g/dL, 95% CI (0.04, 0.73); p = 0.03). According to eight studies, ferric citrate was found to be cost-effective treatment in comparison to control drugs. Most of the adverse events (AE) following ferric citrate treatment were mild at most.

Collectively, our review suggests that iron-based phosphate binder, ferric citrate is an effective and safe treatment option for CKD patients with hyperphosphatemia and anemia. More importantly, this alternative treatment may also less expensive. Nevertheless, more scientific studies are warranted to validate our findings.