Addressing the issue of bias in observational studies: Using instrumental variables and a quasi-randomization trial in an ESME research project

Denosumab vs. bisphosphonates in primary osteoporosis: a meta-analysis of comparative safety in randomized controlled trials

Denosumab and bisphosphonates for primary osteoporosis are generally well-tolerated, but their comparative safety remains unclear. We aimed to explore the comparative safety of denosumab and bisphosphonates in primary osteoporosis. Databases such as PubMed and Google Scholar were searched for relevant peer-reviewed randomized controlled trials published in English (as of December 2023). Trials comparing adverse events (AE) between denosumab and bisphosphonates in patients with primary osteoporosis were investigated. Data were pooled using a fixed- or random-effects model to determine the risk ratios (RR) and 95% confidence intervals (CIs) for various AEs in patients treated with denosumab in comparison to patients treated with bisphosphonates. Eleven trials (5,545 patients; follow-up period: 12-24 months) were included in this meta-analysis. All trials had a risk of bias (e.g., reporting bias linked to secondary endpoints and selection bias linked to random allocation). In comparison to bisphosphonates, denosumab was significantly associated with less withdrawal due to AEs (RR = 0.49; 95% CI 0.34-0.71), more five-point major adverse cardiovascular events (RR = 2.05; 95% CI 1.03-4.09), more cardiovascular AEs (RR = 1.61; 95% CI 1.07-2.41), more infections (RR = 1.14; 95% CI 1.02-1.27), more upper respiratory tract infections (RR = 1.56; 95% CI 1.08-2.25), less vertebral fractures (RR = 0.54; 95% CI 0.31-0.93), and less abdominal pain (RR = 0.44;95% CI 0.22-0.87). We explored the comparative safety of denosumab and bisphosphonates for primary osteoporosis, some of which could be attributed to their beneficial effects. However, all trials had a risk of bias. Further investigations are required to confirm our results.

Move-in Ready or Fixer-Upper? VC Specialization and Start-up Innovation

Extant scholarship typically assumes that VC firms prefer to pick winners. I offer an alternative perspective: that specialist VC firms can select less attractive start-ups—with innovative potential but in need of help—and then contribute to the start-ups’ innovative processes so they can achieve their potential. The analogy is buying a fixer-upper house, which, with the right help, can be brought to the level of one that is move-in ready. I argue that specialist (versus generalist) VC firms in the syndicate have superior commercialization knowledge and specialized resource networks, and they can choose to follow a move-in-ready strategy (select winners) or a fixer-upper strategy (build winners). This choice is contingent on the research environment and how unique the help from the specialist VC firm is: in well-developed research environments, a specialist adds less value and may follow a move-in-ready strategy; in less-developed research environments, a specialist adds more value and may follow a fixer-upper strategy. I leverage an ideal empirical context, global biotechnology VC-backed start-ups, over the period 1996–2006, when the biotech industry was established in the United States and developing in 25 other countries, and highlight qualitative insights from 20 interviews with investors in seven countries.