Systematic review of economic evaluations and cost analyses of guideline implementation strategies

Objectives To appraise the quality of economic studies undertaken as part of evaluations of guideline implementation strategies; determine their resources use; and recommend methods to improve future studies. Methods Systematic review of economic studies undertaken alongside robust study designs of clinical guideline implementation strategies published (1966-1998). Studies assessed against the BMJ economic evaluations guidelines for each stage of the guideline process (guideline development, implementation and treatment). Results 235 studies were identified, 63 reported some information on cost. Only 3 studies provided evidence that their guideline was effective and efficient. 38 reported the treatment costs only, 12 implementation and treatment costs, 11 implementation costs alone, and two guideline development, implementation and treatment costs. No study gave reasonably complete information on costs. Conclusions Very few satisfactory economic evaluations of guideline implementation strategies have been performed. Current evaluations have numerous methodological defects and rarely consider all relevant costs and benefits. Future evaluations should focus on evaluating the implementation of evidence based guidelines. Keywords: Cost-effectiveness analysis, physician (or health care professional) behaviour, practice guidelines, quality improvement, systematic review.Peer reviewedAuthor versio

The Sanandaj–Sirjan Zone in the Neo-Tethyan suture, western Iran: Zircon U–Pb evidence of late Palaeozoic rifting of northern Gondwana and mid-Jurassic orogenesis

The Zagros Orogen, marking the closure of the Neo-Tethyan Ocean, formed by continental collision beginning in the late Eocene to early Miocene. Collision was preceded by a complicated tectonic history involving Pan-African orogenesis, Late Palaeozoic rifting forming Neo-Tethys, followed by Mesozoic convergence on the ocean\u27s northern margin and ophiolite obduction on its southern margin. The Sanandaj-Sirjan Zone is a metamorphic belt in the Zagros Orogen of Gondwanan provenance. Zircon ages have established Pan-African basement igneous and metamorphic complexes in addition to uncommon late Palaeozoic plutons and abundant Jurassic plutonic rocks. We have determined zircon ages from units in the northwestern Sanandaj-Sirjan Zone (Golpaygan region). A sample of quartzite from the June Complex has detrital zircons with U-Pb ages mainly in 800-1050 Ma with a maximum depositional age of 547 ± 32 Ma (latest Neoproterozoic¿earliest Cambrian). A SHRIMP U-Pb zircon age of 336 ± 9 Ma from gabbro in the June Complex indicates a Carboniferous plutonic event that is also recorded in the far northwestern Sanandaj-Sirjan Zone. Together with the Permian Hasanrobat Granite near Golpaygan, they all are considered related to rifting marking formation of Neo-Tethys. Scarce detrital zircons from an extensive package of metasedimentary rocks (Hamadan Phyllite) have ages consistent with the Triassic to Early Jurassic age previously determined from fossils. These ages confirm that an orogenic episode affected the Sanandaj-Sirjan Zone in the Early to Middle Jurassic (Cimmerian Orogeny). Although the Cimmerian Orogeny in northern Iran reflects late Triassic to Jurassic collision of the Turan platform (southern Eurasia) and the Cimmerian microcontinent, we consider that in the Sanandaj-Sirjan Zone a tectonothermal event coeval with the Cimmerian Orogeny resulted from initiation of subduction and closure of rift basins along the northern margin of Neo-Tethys

Early Palaeozoic continental growth in the Tasmanides of northeast Gondwana and its implications for Rodinia assembly and rifting

Gondwana formed in the Neoproterozoic to Cambrian mainly from collision along the East African and Kuunga orogens at about the same time that the Gondwana palaeo-Pacific facing margin became a long-lived active margin and formed the Terra Australis Orogen. This orogen, and in particular the Tasman Orogenic Belt (the Tasmanides) sector of eastern Australia, is distinguished by widespread shortening of quartz turbidite successions and underlying oceanic basement, with less abundant island arc assemblages. Early Palaeozoic accretionary development of the Tasmanides followed Rodinia breakup at 800–750 Ma to form the palaeo-Pacific Ocean. In eastern Australia, a second rifting episode at 600–580 Ma is more widely developed with siliciclastic sedimentation and rift-related igneous activity. In parts of the Delamerian Orogen of South Australia and northwestern New South Wales and in the exposed northern Thomson Orogen of north and central Queensland, the rift-related sedimentary successions have a dominant 1.3 to 1 Ga detrital zircon age signature implying local sources. They are considered to be derived from an eastward continuation of the 1.3–1 Ga Musgrave Province in central Australia, which marks a major Late Mesoproterozoic suture between the North Australian and South Australian/West Australian cratons and now buried within continental crust of the Thomson Orogen. Palaeomagnetic data suggest that an intraplate 40° anticlockwise rotation occurred between the North Australian Craton and an amalgam of the West and South Australian cratons during the transpressional Petermann Orogeny in central Australia at 650 to 550 Ma and overlapped the 600–580 Ma rifting event. The zone of rotational intraplate shearing is considered to have remobilised the preceding Late Mesoproterozoic suture and provides a marker in Rodinia that supports the AUSMEX reconstruction. Detrital zircon of 650–500 Ma, known as the Pacific–Gondwana association, is very widely represented in Phanerozoic sediment of eastern Australia. It may be that an upper crustal igneous assemblage, now removed by erosion, developed in the Petermann Orogeny contributed to part of this age association. However, a primary Antarctic far-field source is favoured. Given that prior to 650 Ma, the unravelled intraplate rotation shows substantial overlap of the Thomson Orogen and the South Australian Craton, much of the former must have developed by continental growth largely after 550 Ma. The Diamantina Structure, which truncates the Mount Isa Province and forms the northwestern margin of the Thomson Orogen, marks the eastern line of intraplate rotation. This zone of crustal weakness continues into the northern Thomson Orogen where it was remobilised in the mid-Palaeozoic to offset the Mossman Orogen and to later facilitate the Late Mesozoic–Cenozoic Townsville Trough and basin, a major feature of the continental margin. Basement cores and bedrock geology of the Thomson Orogen indicate deposition of widespread quartzose turbidites dominated by Pacific–Gondwana detrital zircon ages (650–500 Ma) that were affected by inferred Middle to Late Cambrian deformation and metamorphism (Delamerian Orogeny). The widespread Delamerian event was succeeded by Late Cambrian–Early Ordovician backarc extension and dominantly silicic igneous activity with granites, volcanic and volcaniclastic successions in the northern Thomson Orogen. Ordovician quartz turbidite deposition followed by compressional deformation in the Late Ordovician–Early Silurian Benambran Orogeny and scattered syn- and post-orogenic granitic plutonism is characteristic of northeast Gondwana and dominates rock assemblages of the Lachlan Orogen

Accretion of a Late Ordovician island arc terrane into the northern Tasmanides and its implications for orogenesis

[Extract] Siluro-Devonian tracts of the northern Tasmanides largely consist of accretionary complex rocks which formed outboard of forearc and arc elements. For the Broken River Province, the accretionary complex consists mostly of poly-deformed turbidites, extensively disrupted by melange, with minor components of MORB-type basalt and chert. However, Late Ordobician volcanics and marine strata form a distinctive terrane located on the inboard margin, the oldest part of the accretionary complex, faulted against pre-Silurian basement and subjacent to an extensive forearc assemblage

Late Neoproterozoic to early Mesozoic sedimentary rocks of the Tasmanides, eastern Australia: provenance switching associated with development of the East Gondwana active margin

The Tasmanides in eastern Australia are the most widely exposed part of the East Gondwana Paleozoic active margin assemblage. Diverse sedimentary assemblages are abundant and include: (1) extensive quartz-rich turbidites and shallow marine to fluvial successions, (2) continental margin and island arc derived sedimentary successions with abundant volcanic lithic detritus, and (3) widespread deep-marine to subaerial successions formed from reworking of older rocks. Apart from island arcs such as the Devonian Gamilaroi-Calliope Arc, most of the Tasmanides sedimentary assemblages formed along or in close proximity to the Gondwana margin. We highlight the interplay and provenance switching between the development of igneous dominated detritus related to adjoining magmatic arcs, such as the Macquarie Arc, and interactions with Gondwana derived sedimentary successions. Paleocurrents and detrital zircon ages indicate periodic influxes of mainly quartz-rich sand derived from the East Gondwana margin and adjacent interior with a common Pacific-Gondwana detrital zircon age signature (600-500 Ma), especially in the Cambrian, Early to Middle Ordovician, and Middle Triassic. A major quartzose turbidite deposit formed in an oceanic setting was accreted to the northern New England accretionary complex in the Late Carboniferous. This contrasts with the bulk of the Devonian to Carboniferous succession of the southern New England Orogen, which is dominated by volcaniclastic input with minor Gondwana-derived detritus. Surprisingly, even the base of the intraoceanic Macquarie Arc shows detrital zircon ages indicative of Gondwana input. The prevalence of Gondwana clastic input into the Tasmanides shows that much of the orogenic belt developed in an active continental margin setting with limited strike-slip displacements, and apart from offshore island arcs, lacks exotic terranes

Coeval basin formation, plutonism and metamorphism in the Northern Tasmanides: extensional Cambro-Ordovician tectonism of the Charters Towers Province

The Charters Towers Province, of the northern Thomson Orogen, records conversion from a Neoproterozoic passive margin to a Cambrian active margin, as characteristic of the Tasmanides. The passive margin succession includes a thick metasedimentary unit derived from Mesoproterozoic rocks. The Cambrian active margin is represented by upper Cambrian-Lower Ordovician (500-460 Ma) basinal development (Seventy Mile Range Group), plutonism and metamorphism resulting from an enduring episode of arc-backarc crustal extension. Detrital zircon age spectra indicate that parts of the metamorphic basement of the Charters Towers Province (elements of the Argentine Metamorphics and Charters Towers Metamorphics) overlap in protolith age with the basal part of the Seventy Mile Range Group and thus were associated with extensional basin development. Detrital zircon age data from the extensional basin succession indicate it was derived from a far-field (Pacific-Gondwana) primary source. However, a young cluster (<510 Ma) is interpreted as reflecting a local igneous source related to active margin tectonism. Relict zircon in a tonalite phase of the Fat Hen Creek Complex suggests that active margin plutonism may have extended back to ca 530 Ma. Syntectonic plutonism in the western Charters Towers Province is dated at ca 485-480 Ma, close to timing of metamorphism (477-467 Ma) and plutonism more generally (508-455 Ma). The dominant structures in the metamorphic basement formed with gentle to subhorizontal dips and are inferred to have formed by extensional ductile deformation, while normal faulting developed at shallower depths, associated with heat advection by plutonism. Lower Silurian (Benambran) shortening, which affected metamorphic basement and extensional basin units, resulted in the dominant east-west-structural trends of the province. We consider that these trends reflect localised north-south shortening rather than rotation of the province as is consistent with the north-south paleogeographic alignment of extensional basin successions